New Lead Emerges in 1992 Murder of Grinnell College Student Tammy Zywicki
Illinois State Police and the FBI announced a potential new lead in the decades-old murder of Tammy Zywicki, a Grinnell College student whose brutal killing in 1992 has haunted Iowa and the Midwest for 34 years. While no suspect has been named, investigators are seeking public help regarding a deceased woman who may have traveled with the unknown truck driver seen near Zywicki's disabled car.
Zywicki, 21, was driving back to Grinnell College in Iowa after dropping off her brother at Northwestern University when her car broke down on Aug. 23, 1992, near mile marker 83 on Interstate 80, just outside Ottawa in LaSalle County. Two days later, her 1985 Pontiac T1000 was found abandoned on the interstate. On Sept. 1, 1992, a truck driver discovered her body along Interstate 44 near Mount Vernon, Missouri. She had been stabbed to death and sexually assaulted.
The case has remained unsolved for more than three decades, but investigators now believe a woman named Thersa 'Teri' Belenske, who died in 2014, may hold clues. Belenske, whose maiden name was Vega, was known to hitchhike and may have been traveling with the unknown truck driver before Zywicki's death. She is not a suspect, but a person of interest, according to Illinois State Police.
Who Was Teri Belenske?
Belenske was 32 at the time of Zywicki's murder and died in 2014 at age 54. State police have released a 2009 photo of her and an AI-generated image of what she may have looked like in 1992. Investigators are seeking information about her from the late 1980s through the mid-1990s, noting ties to California cities including Oceanside, Vista, Pomona, San Bernardino, and Fontana.
'We're asking anyone who knew Belenske or traveled with her during that time to come forward,' an Illinois State Police spokesperson said. 'Even the smallest detail could help break this case open.'
A Case That Shook the Midwest
Zywicki's disappearance and murder drew national attention. Her parents flew from their home in Marlton, New Jersey, to help police. Her classmates at Grinnell held candlelight vigils, hoping she would be found alive. But nine days after she was last seen, her body was discovered.
Investigators believe Zywicki was not killed where her body was found. They suspect she was stabbed to death elsewhere, and the killer drove her body across Illinois and Missouri before dumping it along I-44.
'It's really just one of those surreal things when you're in it,' her brother Dean Zywicki told CBS News Chicago in 2023. 'You push the reality aside just trying to focus on finding her.'
Previous Suspects and a Cold Trail
Over the years, several suspects were investigated. Lonnie Bierbrodt, a trucker and felon on parole, was questioned in 1993. Former Illinois State Police investigator Martin McCarthy said in 2014 that he believed Bierbrodt was the killer, but Bierbrodt was released for lack of evidence and died in 2002. The multistate task force disbanded in February 1993.
Despite the cold trail, those who care have never given up. The 'Who Killed Tammy Zywicki' Facebook group, started in 2009, has grown to 7,780 members, up from 5,725 three years ago. Group administrator Patrick Jones said the group remains active and hopeful.
How You Can Help
Illinois State Police are asking anyone with information about Belenske or her travels in the late '80s or early '90s to contact the ISP Investigative Tips page or call 1-800-CALL-FBI. Callers may remain anonymous. The FBI is offering a $50,000 reward for information leading to the identification of the person or people responsible for Zywicki's murder.
An upcoming Illinois State Police podcast will also address the new lead. For Iowans who remember the case or have any information, this is a chance to bring closure to a family that has waited 34 years.
Frequently Asked Questions
Who was Tammy Zywicki?
Tammy Zywicki was a 21-year-old Grinnell College student from Marlton, New Jersey, who was murdered in 1992 while driving back to Iowa after visiting her brother at Northwestern University.
What is the new lead in the Zywicki case?
Investigators are seeking information about Thersa 'Teri' Belenske, a deceased woman who may have traveled with the unknown truck driver seen near Zywicki's car. She is a person of interest, not a suspect.
Is there a reward for information?
Yes, the FBI is offering a $50,000 reward for information leading to the identification of the person or people responsible for Zywicki's murder.