A man known as the “Riverside Prostitute Killer” haunted the California region during the late 1980s and early 1990s. He targeted women involved in sex work, then cruelly left their bodies behind.

Retired criminalist Steven Secofsky from California’s Department of Justice and Detective Christine Keers from Riverside Police collaborated to identify the killer behind the deaths of at least twelve women. Their investigation is detailed in the show Unknown Serial Killers of America, shown on Sundays at 7/6c on Oxygen. Their findings pointed to the notorious serial killer William “Bill” Suff, though the exact number of his victims remains uncertain.

Keers expressed her belief that the number of victims was probably over 30. She commented on the lack of media coverage, attributing it to the outdated attitudes towards victims connected with sex work and drug use.

“I believe that to be true,” she told producers.

A series of murders in Riverside County

In November 1990, Secofsky and Keers were called to investigate the homicide of Cheryl Coker, whose nude and strangled body was found “strategically” posed in a dumpster within the Riverside city limits, according to Secofsky. The victim’s breasts were “cut off and thrown up an embankment about 50 feet away.”

“We never seen anything like that before,” said Keers.

Coker’s case wasn’t unlike a December 1989 investigation belonging to one of Secofsky’s colleagues. In that case, a sex worker named Tina Leal was stabbed in the chest, and her breasts were also mutilated. Clean socks on Leal’s partially dressed body indicated someone neatly placed her body in the dirt.

“She was also brutally beaten and strangled,” Secofsky added.

Victims showed up elsewhere around Riverside: In January 1990, authorities discovered Darla Ferguson and then Carol Miller one month later. Their bodies were nude, strangled, and posed.

In December 1990, one month after Secofsky and Keers investigated the Coker crime scene, the unclothed body of Susan Sternfeld was found near a dumpster. The killer positioned her body so the soles of her feet touched and her knees fell outward to expose her genitalia.

“I knew right then we were dealing with a serial killer,” Keers told Unknown Serial Killers of America. “We have to catch this guy, or we would have another victim.”

A serial killer task force is created

Roughly 25 law enforcement officials teamed up to create a task force. Together, they shared common evidence between the crime scenes, including shoe prints, tire tracks, plus carpet fibers and cat hairs found with each victim. Profilers from the FBI were called to help identify the killer’s probable traits.

According to Forensic Psychologist Dr. Rachel Toles, the suspect likely had a “bizarre” relationship with his mother, as was the case for many murderers who targeted sex workers. Oftentimes, serial killers came from controlling and domineering mothers who commanded high expectations and ultimately caused their child’s identity to erode.

“If mother is giving them attention, they feel valuable, but if mother is not giving them attention, they feel worthless,” said Dr. Toles. “And, in fact, when they go ahead and kill the sex worker, there’s a part of them that’s almost reenacting their own murder — just killing the worst part of themself.”

Keers and other officials canvassed University Avenue, a section of town frequented with sex work and a place familiar to the victims. In time, contemporaneous media outlets dubbed the elusive murderer the “Riverside Prostitute Killer.”

Still, there was little for authorities to work with, and the body count continued to rise. On January 19, 1991, the body of local sex worker Kathleen Puckett was discovered near a dump site.

“I felt the killer was treating these girls like they were trash, but most of the girls came from wholesome families,” Keers maintained. “They had children that loved them, their mothers, their grandmothers loved them.”

A killer shows no sign of stopping

One of the more challenging crime scenes came with their seventh victim, a deaf mother named Cherie Payseur, whose naked body was discovered posed behind a Riverside bowling alley. Amidst processing the crime scene, nearby sprinklers went off, eliminating much of the evidence left by what Keers called a “ruthless killer.”

Payseur’s April 1991 homicide came months after Puckett’s, and police believed the killer struck at that specific time because newspapers reported the formation of the task force following a dead-end lead in Wisconsin.  

Victim number eight, Sherry Latham, was found in July 1991, followed by the August 1991 discovery of murder victim Kelly Hammond.

“It just broke my heart that she was murdered,” Keers told Unknown Serial Killers of America. “I left the scene of Kelly Hammond and went down to University [Avenue] because I knew she had a good friend that was down there.”

The good friend was Kelly Whitecloud, and her information to Keers would be their most significant lead yet.

According to Keers, Whitecloud — a reported sex worker — claimed she’d been recently picked up by a John that fit the bill. Whitecloud said she asked the unnamed man to bring her to McDonald’s for a hot fudge sundae before she planned to perform sexual favors in exchange for cash.

Whitecloud explicitly said she wanted nuts on the bottom of the ice cream and not the top, according to Keers. However, Whitecloud grew unhappy when the order was returned with the nuts on top, claiming the stranger said he’d deduct the cost of the ice cream from what he’d owe her for sex.

“So, she tells him to get screwed and gets out of the van, and he drives off,” said Keers.

Whitecloud reportedly told Keers she then watched the man drive across the street and pick up victim Kelly Hammond, prompting Whitecloud to call out, “He’s cheap! Don’t get in with him!”

With Whitecloud’s help, police created a composite sketch of the suspect, describing him as a 5-foot,10-inch white male with metal-framed eyeglasses. She also provided crucial information about his vehicle, a two-toned, gray van similar to a Chevrolet Astro.

A search for a suspect

One month later, in September 1991, Catherine McDonald became the killer’s 10th victim.

“The violence on her was horrendous,” said Keers. “This girl had her throat slit so bad it was almost like she was being decapitated.”

Investigators believed the killer chose McDonald because she was Black, as news outlets had just disseminated information that the suspect targeted only white females.

In October 1991, mother-of-six Delliah Zamora became victim number 11, according to her eldest daughter, Alicia Zavala. Zavala said that despite her mother’s issues with substance abuse, the family was “really close” and loving.

“My mom was an amazing person; she just had her struggles, just like everyone else,” Zavala told Unknown Serial Killers of America. “I couldn’t understand why anybody would do that to my mom; she was such a good person.”

On December 23, 1991, the body of mother-of-three Eleanor Casares was found in an orange grove in Riverside. She was fatally stabbed in the chest, and, like some of the other victims, her right breast was removed and tossed off into the distance.

Steven Secofsky from the D.O.J. noticed two brands of tires from a vehicle at the Casares crime scene: one tire was made by Yokohama, and the other was a Dunlop.

“They were consistent with some of the tire tracks I saw at several of the other crime scenes,” Secofsky said.

In a race to catch a serial killer, investigators hoped Whitecloud’s information could help. Two weeks later, patrol officers stopped a man matching the suspect’s description driving on University Avenue.

For Keers, the van’s tires — made by both Yokohama and Dunlop — led her to believe they’d caught their serial killer, then identified as William “Bill” Suff. Authorities arrested him at the traffic stop on charges of driving with a suspended license.

About serial killer suspect William “Bill” Suff

Suff was a married father born in Torrance, California, the first of five children. According to Dennis St. Pierre — who cowrote The Riverside Killer with Detective Keers — Suff took on the role of patriarch after his father abandoned the family.

“The mother was always very strict, very dominating, very domineering, and very critical,” St. Pierre explained.

A deeper look into his background revealed Suff was once convicted of murder in Texas.

In the 1970s, Suff and his first wife, Teryl, shared a young son and an infant daughter.

“Bill’s relationship and marriage to his first wife, Teryl, was very dysfunctional from the very beginning,” Paul Zellerbach, former Deputy District Attorney of Riverside County, told Unknown Serial Killers of America. “Bill Suff was very possessive and controlling, and there were false allegations that she might be cheating on him.”

St. Pierre claimed Suff “began to spiral,” arriving at the belief that the children were not his.

On September 23, 1973, Suff violently beat their two-and-a-half-month-old girl to death and served 10 years of a 70-year sentence, something Keers called “mind-boggling.”

Teryl was also convicted and sentenced to 70 years in connection with the baby’s death. However, her conviction was overturned on appeal a year or two later on the grounds of insufficient evidence.

William Suff goes to trial

At the time of his January 9, 1992 arrest, Suff worked as a driver for the county. It would take three years to build a case, though investigators eventually linked him to fibers and cat hair found at the crime scenes. Shoe prints would also seal the deal. 

During this time, detectives linked Suff to the 1989 unsolved murder of another sex worker, Kimberly Lyttle. So, when his trial began in January 1995, he faced 13 murder charges in total.

“It was like nothing fazed him,” Secofsky said. “He didn’t show remorse. He didn’t show any emotion. It was disturbing.”

Ultimately, thanks to the physical evidence collected at the crime scenes, a jury found Suff guilty of 12 of the 13 murders. He was not convicted for the murder of Cherie Payseur due to physical evidence that could have been used against him being destroyed by the crime scene’s nearby sprinklers.

He was sentenced to death, though many believe he is guilty of killing far more women.

“He committed many others in other counties, but they decided not to pursue those murders because Mr. Suff received 12 death penalty verdicts in my case,” Zellerbach said. “And you can only kill a man once.”

In 2019, the death penalty was overturned in the state of California, though Suff remains on San Quentin’s death row.

In August 2024, he confessed to the 1984 murder of Cathy Ann Small.

Don’t miss all-new episodes of Unknown Serial Killers of America on Oxygen.