Iowa’s serial killers include several long-haul truck drivers who used the state’s interstate network as cover, a handful of historical figures, and a mass murderer whose 1962 killings still rank among the worst crimes in state history. The best-documented cases involve Clark Perry Baldwin of Waterloo, Robert Ben Rhoades of Council Bluffs, and Harry Edward Greenwell, who died in New Albin before being identified as the I-65 Killer. Iowa is also the setting for unproven allegations against Donald Studey and a heavy backlog of unsolved homicides that the state has recently begun working more aggressively.
Clark Perry Baldwin
Clark Perry Baldwin, a long-haul truck driver from Waterloo, was arrested on May 6, 2020, after DNA taken from a Walmart shopping cart and his household garbage matched evidence from three cold-case murders in Tennessee and Wyoming.1Iowa Department of Public Safety. Waterloo Man Charged in Tennessee and Wyoming Cold Case Homicides
His known victims were Pamela McCall, a 32-year-old killed in Tennessee in 1991, and two women whose bodies were found along Wyoming interstates in 1992. Both women went unidentified for decades. “Bitter Creek Betty,” found near Interstate 80, was eventually identified as Irene Vasquez. “I-90 Jane Doe,” found near Interstate 90, was identified as 21-year-old Cindi Arleen Estrada, who was pregnant when she died. Wyoming authorities named both women publicly on July 17, 2025.2Des Moines Register. Accused Serial Killer Clark Baldwin Dies, Wyoming Victims Identified
Baldwin was convicted of the first-degree murder of McCall and her unborn child on May 5, 2025, and sentenced to life in prison.3NewsChannel 5. Justice Served After Serial Killer Convicted in a Decades-Long Cold Case He never stood trial in Wyoming. He suffered a heart attack and died on July 18, 2025, a day after his Wyoming victims were identified, and the pending charges became moot.4Cowboy State Daily. Accused Serial Killer Suspected of Murdering 2 Women in Wyoming Dies in Tennessee
Investigators also considered Baldwin a suspect in the 1992 murder of Rhonda Knutson, a 22-year-old convenience store clerk bludgeoned at a Phillips 66 in Williamstown, Iowa. Baldwin lived in nearby Nashua at the time and reportedly matched a composite sketch of a trucker seen at the store shortly before the killing.5Forensic Magazine. Serial Killer Suspect Dies 1 Day After Third Victim Identification He never admitted involvement, and Chickasaw County Sheriff Ryan Shawver said after Baldwin’s death that he had not been ruled out.6KAAL TV. For Over 3 Decades, the Murder of Rhonda Knutson Has Remained Unsolved
Robert Ben Rhoades
Robert Ben Rhoades, born November 22, 1945, grew up in Council Bluffs and attended Monticello High School before enlisting in the Marine Corps. After a dishonorable discharge, he returned to Council Bluffs, married, and eventually became a long-haul trucker.7Radford University. Robert Ben Rhoades Case Study He is suspected of killing as many as 50 people. He was convicted of three.8Des Moines Register. Why an FBI Author Says Database Could Solve Highway Serial Killings
Prosecutors described a “mobile torture chamber” concealed in the cab of his truck, with a hidden compartment and ceiling-mounted handcuffs used to restrain female victims.9ABC News. Texas Trucker Traveling Torture Chamber Admits Murders His documented victims included 14-year-old runaway Regina Walters, killed in 1990, and newlyweds Patricia Walsh and Douglas Scott Zyskowski, who disappeared while hitchhiking from Seattle in November 1989. Rhoades killed Zyskowski shortly after picking the couple up in Texas, then held Walsh captive for seven days before murdering her. Zyskowski’s body was found along Interstate 10 in Texas; Walsh’s remains were found months later in Utah.
Rhoades was arrested in Arizona on April 1, 1990, after assaulting another victim. He pleaded guilty to Walters’s murder in Illinois in 1992 and received life without parole. In March 2012 he pleaded guilty to two counts of capital murder in Texas for Walsh and Zyskowski and received a second stacked life sentence.9ABC News. Texas Trucker Traveling Torture Chamber Admits Murders
Harry Edward Greenwell
Harry Edward Greenwell, identified through genetic genealogy as the “I-65 Killer,” was living in New Albin, Iowa, when he died of cancer in January 2013 at age 68.10KCCI. Man Believed to Be I-65 Killer Died in Iowa He was never prosecuted. Indiana State Police confirmed the DNA match through kinship testing at what they called a “99.9999% positive” level.
Greenwell was linked to the sexual assaults and murders of three women along the Interstate 65 corridor between 1987 and 1990: Vicki Heath in Elizabethtown, Kentucky, in 1987, and Margaret “Peggy” Gill and Jeanne Gilbert in Merrillville and Remington, Indiana, in 1989. He was also connected to a 1990 sexual assault of a surviving victim in Columbus, Indiana.11ABC News. I-65 Killer Who Murdered Women in 1980s Identified by DNA Evidence Authorities named him publicly in April 2022 and continue to look into whether he committed other unsolved crimes in the Midwest.
Jake Bird
Jake Bird, born in 1901, claimed responsibility for as many as 46 murders across ten states, all committed with an axe or hatchet. His Iowa connection came through attacks in Carter Lake, near Omaha. After being arrested in Omaha in 1928, he was transferred to Iowa to stand trial for those attacks.12North Omaha History. A History of Jake Bird in North Omaha
Bird was eventually tried and convicted in Washington State and executed by hanging in 1949. In 1948, while awaiting execution, he confessed to the murder of an 8-year-old child named Harvey Boyd in East Omaha. Another man, Clarence Lukehart, had already served 19 years in prison for that killing.
Gayno Gilbert Smith
In 1962, 24-year-old farmhand Gayno Gilbert Smith killed six people, including five members of the McBeth family, in Keokuk County. Smith shot his uncle and aunt, Andrew and Mrs. McBeth, along with three of their children: 19-year-old twins Amos and Anna, and 17-year-old Donna Jean Kellogg. A fourth child, 15-year-old Patsy Lou McBeth, survived a shoulder wound. Smith had also bludgeoned his stepmother, Luanita Smith, to death the previous October and buried her in a shallow grave near their home in Hedrick.13Daily Iowan. Daily Iowan Report on Gayno Gilbert Smith Sentencing
Smith was captured near Drakesville on Memorial Day. Judge C. R. Carson found him guilty of first-degree murder for the five McBeth killings and sentenced him to six consecutive life terms at hard labor at the Iowa State Penitentiary in Fort Madison. Smith separately pleaded guilty to second-degree murder in the death of his stepmother. Psychiatric evaluators found no evidence of mental disease or defect at the time of the crimes. Carson said the consecutive sentences were meant to ensure “the defendant can never be released.”
The Donald Studey Allegations
In October 2022, Lucy Studey-McKiddy told Newsweek that her father, Donald Dean Studey, who died in 2013, had murdered between 50 and 70 people over three decades on his property near Thurman in Fremont County.14CNN. Iowa Serial Killer Claim: Donald Studey She said the victims were mainly transients and sex workers and that her father buried five or six bodies a year in or near a 90-foot stone well on the property. McKiddy said she helped move the bodies with a wheelbarrow in summer and a toboggan in winter.15People. Inside Donald Studey Life: Green Hollow Murders
Fremont County Sheriff Kevin Aistrope said cadaver dogs brought to the site “did indicate in the area,” though the alerts were not specifically pinpointed over the well.14CNN. Iowa Serial Killer Claim: Donald Studey In December 2022, the Iowa Division of Criminal Investigation conducted a three-day excavation with FBI and local law enforcement support. The DCI concluded that “after exhaustive efforts, no evidence or other items of concern were recovered.” Assistant Director Mitch Mortvedt noted that cadaver dog alerts are not always reliable as a sole source of evidence.16ABC 7 Chicago. Iowa Serial Killer Update: Woman Claims Dad Was Donald Studey
Lucy Studey-McKiddy has disputed the thoroughness of that investigation, calling it a “sham dig.” Her older sister, Susan Studey, has rejected the allegations entirely, saying their father “was not the man she makes him out to be.” A second excavation in May 2025 again failed to locate human remains, though cadaver dogs alerted at several spots. Forensic archaeologist William Belcher noted that while nothing was found in the areas searched, “that doesn’t mean there’s nothing out there in places that we didn’t look.”15People. Inside Donald Studey Life: Green Hollow Murders No definitive proof of the alleged killings has been found. Because Studey died in 2013, no prosecution is possible regardless of what any future investigation might turn up.
Why Iowa Keeps Appearing in These Cases
Interstates 35, 80, and 29 all cross Iowa, and the FBI’s Highway Serial Killings Initiative has flagged these corridors as significant. The FBI’s database tracks roughly 850 victims and 450 suspects connected to highway-related murders of women nationwide, with about 200 cases still active and unsolved.8Des Moines Register. Why an FBI Author Says Database Could Solve Highway Serial Killings
Frank Figliuzzi, a retired FBI special agent and author of Long Haul: Hunting the Highway Serial Killers, has said that many rural law enforcement agencies are either unaware of the FBI’s database or lack the resources to submit information to it. Long-haul trucking is the most common profession among known highway serial killers, with about 25 currently imprisoned nationwide. Iowa’s cases involving Baldwin, Rhoades, and Greenwell all fit that pattern.
Prominent Unsolved Cases
About one in three Iowa homicides over the past 30 years has gone unsolved.17Iowa Starting Line. 7 Iowa Cold Cases That Remain Unsolved Three cases sit near the top of that list.
Jodi Huisentruit
Mason City morning news anchor Jodi Huisentruit disappeared on June 27, 1995, with signs of a struggle near her vehicle. She was declared legally dead in 2001, and no arrests have been made.18Fox 9. Jodi Huisentruit: 31 Years Since Morning News Anchor’s Disappearance A portion of a 2017 search warrant in the case was unsealed in March 2025. Iowa private investigator Steve Ridge has publicly claimed to have identified a potential suspect, citing a woman who alleges the individual confessed to her, and has shared his findings with the Iowa DCI.19KTTC. Private Investigator Says He Found Potential Suspect Behind Jodi Huisentruit’s Disappearance
Lyric Cook-Morrissey and Elizabeth Collins
Cousins Lyric Cook-Morrissey, 10, and Elizabeth Collins, 8, were abducted on July 13, 2012, while riding their bikes in Evansdale. Their bicycles were found near Meyers Lake, and their bodies were discovered five months later in the Seven Bridges Wildlife Area, roughly 20 to 25 miles away.20Iowa Department of Public Safety. Evansdale Murder Investigation Continues 10 Years Later The DCI has never publicly named a suspect or motive, and investigators have pursued more than 2,000 leads. Since April 2025, the DCI Crime Lab has been running case evidence through “Starmix,” software designed to isolate individual DNA profiles from complex mixtures.21KCCI. New DNA Technology Being Used in Evansdale Cousin Abduction Case 13 Years Later Five investigators remain assigned.
Tammy Jo Zywicki
Grinnell College student Tammy Jo Zywicki, 21, disappeared on Interstate 80 in central Illinois on August 23, 1992, while driving to school. Her body was found nine days later in a ditch off Interstate 44 in Missouri. She had been sexually assaulted, stabbed eight times, and wrapped in a blanket bearing a Kenworth truck logo, sealed at both ends with duct tape.22Des Moines Register. Killing of Grinnell College Student Tammy Jo Zywicki Remains Unsolved Over 30 Years Later
The primary suspect was Lonnie Bierbrodt, a deceased truck driver who lived in Missouri near where the body was found, drove a Kenworth, admitted being in the area the day Zywicki vanished, and sold and steam-cleaned a Datsun pickup matching a witness description shortly after the murder. His ex-wife reportedly had a musical watch similar to one stolen from Zywicki but refused to cooperate. Bierbrodt died in 2002 without being charged. Convicted serial trucker Bruce Mendenhall has also been considered a possible suspect but has not been linked by direct evidence.23Springfield State Journal-Register. After 20 Years, Mother Copes The case remains open with the Illinois State Police and the FBI.
Iowa’s Cold Case Unit
The Iowa Attorney General’s office re-established a Cold Case Unit in 2024 under Attorney General Brenna Bird. The Iowa Legislature allocated about $500,000 to fund a team of three investigators and one prosecutor.24KWQC. Iowa’s Most Notorious Murders: AG Launches Cold Case Task Force The unit works with local law enforcement on more than 400 unresolved homicides, suspicious missing persons cases, and unidentified human remains.
Its early results include the March 2025 arrest of Robert Davis in the 1989 murder of Barbara Lenz, followed by his conviction for second-degree murder on March 31, 2026, and a 50-year sentence. Kristin Ramsey was arrested and charged with first-degree murder on March 17, 2026, in the 2011 shooting death of West Des Moines realtor Ashley Okland after a grand jury indictment. A suspect in the 2020 murder of Christian Balke-Thompson was arrested in January 2026.25Des Moines Register. Iowa Attorney General Brenna Bird Cold Case Unit Homicides Progress
In 2025 the office distributed decks of playing cards featuring cold case victims to inmates in all nine Iowa state correctional facilities, hoping to draw new leads. The program was funded through law enforcement associations and the Iowa Department of Corrections rather than through taxpayer dollars.26Iowa Attorney General’s Office. Iowa Cold Case Tips can be submitted to the Cold Case Unit at 800-242-5100 or coldcase@ag.iowa.gov.