The Serial Killer Hiding in Plain Sight

DOWNEY, Calif — For months, Toby watched the apartment complex in this quiet, working class Los Angeles suburb every chance he got. He came on his lunch break, after work, on the weekends between his daughter’s playdates. He could tell you the best place to park—by Jimmy's Burgers around the corner—and the nearest liquor store. “Sometimes I spent four or five hours just watching,” Toby said. 

Toby is a project manager, six feet tall with wavy, salt and pepper hair, tanned skin, an athletic build and a gee-whiz feel about him that matches his Subaru Outback. But Toby had become a man possessed. He was convinced that his girlfriend’s murderer lived in one of the low-rise, green stucco apartments. 

Her murder, in Tijuana’s red light district a year and a half earlier in January 2022, had hardly made the news at the time. It was just another death in a city that regularly ranks among the world’s most dangerous. Crimes were rarely solved; even less so when the victims, like Toby’s Mexican girlfriend, were sex workers. 

The disappearance and killing of women in Mexico is a decades-old problem. Instead of being treated as victims, the women themselves are often blamed—because they were out alone at night, or had drunk too much, or even worse, were selling their bodies for sex. Those investigations that do happen are often sloppy and half-hearted, and lack even the most basic forensic work. Famously, the mangled bodies of hundreds of murdered women turned up in the desert around Ciudad Juarez on the Rio Grande River in the 1990s and early 2000s. Only a handful of suspects were ever apprehended. 

But Toby had evidence.

The murder of his girlfriend, Angela Acosta, offered plenty of leads: There was a crime scene, a body, video footage, and cell phone evidence. In the early morning hours after her death—before her body was found and when she was still feared missing—he had tracked her phone to try to glean information about her whereabouts. To his shock, the phone appeared on a residential street in Downey, 130 miles north of Tijuana. 

Toby tried to raise the alarm. Less than 36 hours after Acosta’s body was found, he shared the information about her cell phone turning up in Southern California with an FBI task force officer, while Acosta’s mom told Mexican investigators. He pleaded with them to do something, anything. He pleaded again when Acosta’s Apple Pay was used in the days after her murder—at a Dunkin Donuts and a Vietnamese restaurant. 

“If the FBI had actively contacted the Mexican authorities and said ‘we have information related to a murder in your city,’ things would have gone very differently,” said Toby, who asked to withhold his last name because of the enormous media attention around the case. 

Instead, three weeks after his girlfriend’s body was discovered in a hotel bathroom, another sex worker was brutally murdered in Tijuana. Months later, Mexican authorities declared the murders to be the work of a serial killer. 

U.S. and Mexican authorities hailed the alleged murderer’s eventual arrest as an example of the countries’ close cooperation. But there is another story: About how a lackluster investigation, slow-moving justice system, and a time-consuming extradition process allowed a serial killer to continue preying on sex workers.

It also underscores the vulnerability of women in Mexico, a country marred by violence and impunity. More than 70 percent of women over the age of 15 report suffering some kind of violence, according to the government’s statistics office. Justice is as elusive as violence is commonplace, leaving more than 90 percent of homicides unsolved.

And in Acosta’s case, it would take overwhelming evidence, a single-minded boyfriend, and the brutal killings of at least two other women before authorities intervened. 

The Hong Kong Gentlemen's Club was the killer’s hunting ground. 

Open 24 hours a day, seven days a week, the three-story club employs hundreds of strippers designed to meet any man’s fantasy: skinny women, thick women, women in their thirties, and 18-year-olds with braces. Topless dancers twerk on a table covered in soap and bubbles as men slap dollar bills on their butts and finger them for extra money. Female strippers penetrate each other with dildos to the delight of clients.

The club, one of Mexico’s most famous, attracts clientele from around the world: Russians, Chinese, Mexicans—and especially Americans. VIP customers are picked up at the nearby U.S.-Mexico border in limousines. The club has long been rumored to have cartel ties: During the height of the pandemic, it was one of the few locales to continue operating. It has weathered murders, overdoses and scandals, but the club never stays closed for more than a few days. In August, a manager at the club was executed with a shot to the head while driving in Tijuana. 

The dancers at Hong Kong mostly come from cities far from Tijuana, lured by the appeal of good money. They are poor and trying to make ends meet, or earn enough money to put themselves through school. They make money from tips and the drinks customers buy them—for every drink the club pays them 50 pesos, or roughly $3. The real money comes from prostitution: around $150 for 30 minutes of sex. 

Acosta, Toby’s girlfriend, started working at the club in August 2020. She was from Monterrey—another border city 1,500 miles away—and had been attending medical school, but she struggled when the pandemic hit and classes became virtual. She dropped out and moved to Tijuana to work at Hong Kong. 

On Monday, January 24, 2022, Acosta reported to work in a metallic, blue bikini and knee-high boots topped by rainbow-colored socks. She wore her straight black hair down. She was dancing at the front of the club when an American took notice, said Acosta’s friend, Hadden, who was with her. The man wore a dark sweater, had a light brown complexion and his black hair was shorter on the sides and longer on the top. He was around 30. He invited Acosta for a drink, and Hadden joined.

The man said he was from the U.S. and primarily spoke in English with Acosta, said Hadden, who requested to only use her first name because of the sensitive nature of the case. He didn’t drink alcohol, and was taciturn and serious, she said. The American asked whether the women were interested in astrology. Acosta said she was, and showed him an astrology chart on her phone. The man then said, “It can even tell the day you’re going to die,” Hadden recalled. 

After about 20 minutes, Acosta and the American left for Hotel Cascadas, which is used by the club for prostitution. Security officers guard the halls, but mostly to make sure customers don’t overstay their allotted time, two dancers who work at the club told VICE News. At 10 p.m., Acosta texted her mom as she always did before going with a client: “404 30 min,” she wrote, referring to the hotel room number.

An hour passed. And then two. Acosta’s mom texted and called, but the messages stopped going through and her calls went straight to voicemail. Afraid something had happened, she went to the club to look for her daughter. But the managers refused to help, she said. She was told they couldn’t disturb room 404 because the customer had reserved the room until 1 p.m. the following day. 

Acosta’s mom had already contacted Toby to say she was worried. Toby sped from Los Angeles to Tijuana to also look for Acosta, and when he arrived at Hotel Cascadas around 3 a.m., he pleaded with the staff to review their security cameras. But more than one person told him the security cameras weren’t working, he said. Hadden said staff at the club told her the same.

“They told us for three hours in a row they were going to check the room,” Toby said. “And then they would come back and say ‘we have to wait.’ By the third time they told us that, I lost my mind,” he said. He went to room 404 and banged on the door. The only thing he heard was the humming of a mini fridge. 

When hotel staff finally entered the room at noon the following day, on Jan. 25, they found Acosta dead on the bathroom floor, naked. Her mouth had been stuffed with paper to prevent her from breathing. There was no sign of the American.

As police carried out Acosta’s body on a stretcher, Toby said that one of the hotel’s security guards told him, “She’s gone—overdose.” The rumor was repeated over and over again and by the time Acosta’s friend Hadden returned to the club two weeks later, all of the dancers had been led to believe that Acosta died of a drug overdose, she said.

When Tijuana police interviewed Acosta’s mom, Clara Flores, they also implied Acosta was to blame, she said. “They suggested that she was a drug addict and involved with the wrong people,” Flores said. “They asked if she was ‘rebellious’ or if she had any tattoos.”

An autopsy would later determine that Acosta had no trace of drugs or alcohol in her body. And the security cameras at Hotel Cascadas were, in fact, working. When the footage was eventually turned over to authorities, it offered damning evidence. At 10:13 p.m, Acosta and the American entered room 404. At 11:49, the American left the room. The cameras captured no one else entering or leaving the room, according to court records. 

Thirteen minutes after the customer left room 404, a man fitting his description and wearing the same clothes crossed by foot from Tijuana into San Diego at the San Ysidro Port of Entry.

Months later, Toby learned the American’s identity. He was a U.S. citizen, and, according to prosecutors, his name was Bryant Rivera.

Rivera has not been charged in the U.S. and his lawyer declined to comment.  

Acosta’s murder sent Toby into a spiral of grief and guilt. If only he could have gotten to her earlier. If only Acosta hadn’t worked that night, or had stopped working at the club altogether. The scenarios ran through his head in an endless loop.

The couple met in August 2020 at a party thrown by Hong Kong Gentlemen’s Club. He was 41, she was 19. The pandemic was raging. 

Toby had started going to the club to escape his isolation and meet women. He is good-looking and the dancers doted on him. “I loved being given for free what others had to pay for,” he said.

The first night Toby met Acosta, they stayed up all night talking about music, and Toby asked her on a date. She was funny and beautiful. Soon, Toby was visiting Acosta every weekend in Tijuana. Three months after they first met, he went to her grandfather’s birthday party in Monterrey and met her extended family. He took her on trips around the world—to Colombia, Paris, Berlin, Mexico City. They constantly took videos together—drinking coffee, visiting pyramids, discussing the day’s plans. 

Toby knows what it looks like—dating a sex worker half his age. He also doesn't care. “We talked and FaceTimed every single day. I thought it was ridiculous. I am 40 years old. I don’t really want to Facetime for 45 minutes,” Toby said. “But I never got tired of it. I was in love with her, and I have no doubt that she was in love with me.” 

But they also fought, especially when it came to Acosta’s work at Hong Kong. Toby wanted Acosta to stop working there. There were the personal reasons, of course—Acosta was having sex with other men—but also he feared for her safety.

Acosta refused Toby’s pleas—she didn’t want to depend on him. She had rented a space in Tijuana to open a clothing store and needed the money to get it off the ground.

As soon as he learned Acosta was missing, Toby feared the worst. Acosta had recently acquired a new phone, but it was still linked to her previous phone. Using the old phone, he could see her new phone was in Downey. Some 12 hours later—after Acosta’s body had been found—the phone appeared 50 miles to the east, in Riverside, California.

Flores, Acosta’s mom, said she turned Acosta’s old cell phone over to Mexican investigators in hopes that they would follow up. But they seemed fixated on the idea that Toby was behind the murder, she said. She told investigators they were chasing a dead end, but privately she worried they would try and blame him. She told Toby not to return to Tijuana anytime soon.

A spokesman for the Baja California Attorney General’s office, which oversees homicide investigations in Tijuana, didn’t respond to a request for comment about whether authorities did anything with the information provided by Flores, or if they considered Toby a suspect.

Tijuana was coming off years of record violence, fueled by a brutal cartel war over control of the drug trade. The number of homicides averaged around 2,000 per year, making the border city the bloodiest in all of Mexico. By contrast, New York City—whose population is four times as large—had 433 murders in 2022.  

There were so many corpses in the government morgue in Tijuana that authorities ran out of refrigerators to store Acosta’s body. By the time they turned it over to Flores, around a week after the murder, it had already started to decompose, she said.

Toby channeled his rage and grief into investigating Acosta’s murder. A friend put him in touch with a former Riverside County District Attorney, who in turn connected Toby to FBI task force agent Dane Wilkinson.

Toby told Wilkinson about Acosta’s stolen iPhone and how someone was still using her Apple Pay. Toby wanted to track down the phone—an idea that Wilkinson dissuaded him against because it could undermine evidence. Plus, it was dangerous.

Wilkinson was sympathetic, Toby said, but told him that without a homicide report there was nothing he could do. In the days and weeks after Acosta’s murder, Toby emailed Wilkinson with increasing desperation. 

January 26: “Just the idea that there's the tiniest little thing that I can do for her means the world to me.”

January 27: “Her phone is still pinging in the same location.”

March 30: “Did the Mexican authorities ever reach out or share any information? I don’t expect any details, I just want to know if they’ve lifted a finger to help Angy. They have shared nothing with her mother. We still don’t even have the autopsy.”

Wilkinson said his hands were tied. “We were basically assisting the Mexican authorities if they requested our assistance,” he emailed Toby on July 15, 2022.

In fact, Mexican authorities had already zeroed in on Rivera as a prime suspect. It’s unclear if Wilkinson knew this and didn’t want to tell Toby, or if he simply didn’t know. Wilkinson didn’t respond to requests for comment sent to his email and phone.  

It is, on the whole, much more difficult to be a serial killer these days. Because of improved technology and forensic investigative tools, authorities are much more likely to apprehend would-be serial killers before they have a chance to murder multiple victims. But in Mexico, a mix of impunity, corruption and sheer lack of resources mean perpetrators can go years without being caught. And when they are, the wheels of justice often move at a snail’s pace. 

Rosario Mosso Castro, a veteran reporter with the Tijuana paper Zeta, was the first person to publicly raise the alarm about a possible serial killer hunting sex workers in the city. Her front-page story in March 2022 identified three victims by their first names.

The first was Karen González Argüelles, who worked briefly at Hong Kong Gentlemen’s Club, according to Mosso Castro. She went missing on August 30, 2020 after going on a date with a client. Her body was discovered a few days later in a trash dump in a canyon that separates Tijuana and San Diego. She had been strangled and beaten to death. She left behind a young daughter.

The second victim was Acosta.

The third woman was murdered just three weeks after Acosta. 

The victim, 25-year-old Elizabeth Martínez Cigarroa, was also a sex worker who worked at Hong Kong. She told her family she was going on a Valentine’s Day date with an American man that she met at the club. Days later, on Feb. 17, 2022, her naked body was found in the trunk of her Jeep, which had been abandoned on a commercial street in Tijuana’s red light district. Security camera footage showed a man parking the car.

One month after Martínez Cigarroa’s murder, a judge in Baja California—where Tijuana is located—quietly signed a warrant for Rivera’s arrest, according to documents obtained by VICE News. But the arrest warrant applied only if Rivera were apprehended in Mexico.

Toby didn’t know about any of this. Neither did Acosta’s mom. They had no idea the investigation had advanced at all until November, when Mosso Castro published another blockbuster story that identified the suspected serial killer as 30-year-old “Brayan Andrade Rivera” and included his driver’s license photo.

After Mosso Castro’s story hit the news, the top prosecutor in Baja California confirmed that Mexican authorities were looking for an American. The suspect has “criminal tendencies associated with violent and psychopathic behavior,” then-Attorney General Ivan Carpio Sánchez told reporters. Carpio Sánchez was well-regarded in U.S. circles as being a hard-hitter who stayed up nights working homicide cases. He likened the murderer to notorious serial killer Ted Bundy, a comparison that immediately made headlines across the U.S. 

The implication left by the prosecutor, and repeated in the stories, was that an American serial killer was on the lam. Except Rivera wasn’t on the run, according to documents seen by VICE News. Authorities in both countries were already communicating about him—and knew where to find him.

But knowing Rivera’s whereabouts wasn’t enough. To convince U.S. authorities to arrest Rivera, Mexico would have to go through a lengthy extradition process that regularly takes up to a year or longer. It would mean laying out the evidence against him for a U.S. court to review. 

VICE News tried to reach Carpio Sánchez multiple times to answer questions about the case but never received a response. He resigned from his position as attorney general last month. The same week as his departure, he announced that authorities are investigating Rivera for the murder of a fourth woman in Tijuana whose death had similar hallmarks to the other victims. He didn’t say when the murder took place or provide other details. 

Toby’s search for justice became all consuming. He became a self-taught private investigator. He looked up every possible variation of Bryan Rivera, Brayan Andrade Rivera, and Brian Rivera in California. He paid for no fewer than three databases that offered home addresses, telephone numbers and criminal histories. 

He also reached out to Francisco Cigarroa, the brother of the woman murdered three weeks after Acosta. Cigarroa had been extremely vocal after his sister’s death and denounced authorities for failing to investigate. Now, Cigarroa confided with Toby that an anonymous person had reached out over Facebook and shared Rivera’s address in Downey. 

Toby began driving to the apartment complex every chance he could, hoping for a glimpse of Rivera. 

In May of this year, Toby said he called the FBI field office in Los Angeles and was connected to an agent. He again pleaded for law enforcement to arrest Rivera. “I was calling to say there is a serial killer living here, and I shared his address and name,” Toby said. “He probably thought I was crazy.”

Toby said he never heard back.

He wasn’t the only one reporting Rivera. Shannon Sales, a Los Angeles resident, said she also called the FBI after seeing Rivera’s picture in a story about a serial killer in Tijuana. She recognized him, because it was her ex-boyfriend’s best friend. 

Rivera and Sales’ former boyfriend worked together delivering Amazon packages, and Rivera had come to her house many times, Sales said. Rivera was quiet and awkward. He told her that he was in a relationship with a stripper in Tijuana and that he was in love with her. 

“He always wanted to know something from a woman’s point of view,” Sales said. “Like, ‘do women like to be controlled or do they like guys to be nice?’”

She said she left a voicemail with the FBI and also sent a message through an online portal. She doesn’t remember the exact wording but it was something like: “That serial killer in Tijuana? I know him.” She also said she never heard back.

The FBI declined to comment about the phone calls from Sales and Toby, or its involvement in the case. “I can’t get into that,” a press officer told VICE News.

By late spring, Mexico’s request for Rivera’s provisional arrest and extradition was winding its way through the U.S. justice system, from the State Department to the Department of Justice and eventually to the U.S. Attorney's Office for the Central District of California, which on June 29 asked a federal magistrate judge to approve Rivera’s arrest based on the evidence provided by Mexico.

On July 6., around 5 a.m., a team of U.S. law enforcement officers surrounded an apartment complex in Downey. They zeroed in on the green, second floor apartment with potted geraniums and coleus outside. Sirens blared as the officers called for the residents to step outside with their hands in the air. Rivera appeared in basketball shorts and a T-shirt, a neighbor told VICE News. Authorities arrested him on the spot. It was still dark out. 

Rivera’s arrest came 16 months after a Mexican judge had issued an arrest warrant against him, and 18 months since Acosta’s murder.  

He was picked up just one block from where Acosta’s cell phone pinged in the hours when she was still missing. Authorities found several cell phones among Rivera’s possessions, Toby said an FBI agent told him. Acosta’s appeared to be among them—a Sierra Blue iPhone 13 Pro Max. The FBI wouldn’t confirm whether it had recovered Acosta’s phone.

The U.S. Department of Justice also declined to answer questions about the case, including when U.S. authorities first learned that Rivera was a murder suspect. But a U.S. government official who agreed to speak on condition of anonymity said the extradition process—including Rivera’s arrest—has advanced quickly. “It’s absolutely moving really fast, and it’s because the Mexicans have great evidence,” said the official, describing the case against Rivera as “air-tight.”

Tony Robleto, an FBI border liaison officer from 2011-2017, said U.S. authorities likely knew about Rivera within days of Acosta’s murder. “I guarantee you that within a few days the Mexican authorities had the suspect identified from video and all of that,” Robleto said. “They probably reached out to CBP (U.S. Customs and Border Protection) and said ‘can you check if you have any crossings around this time and look at that.’” 

Robleto said there are steps U.S. authorities could have taken as they waited for Mexico to submit a provisional arrest warrant, like monitoring Rivera or tracking his cell phone in order to alert Mexican authorities if he crossed into Tijuana. It’s unclear if that happened.

Rivera’s arrest took neighbors and co-workers by shock. He was known to keep to himself, but he had never shown signs of a temper or a violent streak. He had never been arrested or charged with a crime. He lived with and took care of his elderly and ailing parents, neither of whom speak English. His father, who is blind, is largely confined to a wheelchair.

A former co-worker at the Mexican restaurant El Taco said Rivera was quiet, almost to the point of mute. He said Rivera got the job at the restaurant because Rivera’s father—who had worked there decades earlier—arrived with Rivera and asked the manager to give his son a job. “If you tried to talk to him, he would look away and just give ‘yes or no’ answers. But he was never disrespectful,” said the co-worker, who asked to withhold his name because of the media attention around the case.

In a court filing, federal public defender J. Alejandro Barrientos requested that the judge release Rivera on bail and noted the lengthy time period it took to arrest him. “Whatever the cause of these delays, the mere fact that they were permitted to occur betray any claim that Mr. Rivera poses an immediate danger to anyone,” Barrientos wrote. 

Rivera’s older sister also pleaded for her brother to be released to her on bail. “The crimes of which my brother is being accused of do not resemble the character of the boy I grew up with and know," she wrote in a statement to the court, describing him as “shy and reserved.” She said when she moved out, “all the responsibility of taking my parents to their doctor appointments, grocery shopping, running errands, etc., fell onto my brother.” 

The judge denied bail. Rivera is expected to be extradited to Mexico in the coming months, marking a triumph for Mexican authorities. While extradition is common, it’s mostly a one-way street of Mexico sending its citizens to the U.S. to face trial and prison time. Rivera is an exception.  

On July 30, two days before Acosta’s birthday, Toby visited her grave in Tijuana. He had always gone accompanied by someone, but this time he went alone. He stayed for hours. He played songs from their playlist—they had sent each other a song a day since the night they met.

He spread rose petals and tied blue balloons to the white cross at her gravesite. He told her everything—about his efforts to obtain justice for her, and how an American had been arrested for her murder. He cried and screamed and sang her happy birthday. Acosta would have been 22.