Open caseUnsolved murder
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In short: An open murder case involving Tammy Jo Zywicki from Utica, Illinois, August 23, 1992. Illinois State Police, with the FBI (Chicago Field Office) is the investigating agency. Tips: Illinois State Police, 815-726-6377.
Our summary of the public record. The small numbers show where each fact comes from. Tap one to see the source.
Tammy Zywicki, 21, was heading back to Grinnell College in Iowa for her senior year on August 23, 1992. She left Evanston, Illinois, that afternoon after dropping her brother off at Northwestern University. According to the FBI, she was last seen with her white 1985 Pontiac T1000 on the shoulder of Interstate 80 near mile marker 83 in LaSalle County, Illinois, between about 3:10 and 4 p.m. An Illinois State Trooper ticketed the car as abandoned later that day, and it was towed on August 24, the same evening her mother told state police she had never arrived at school.
On September 1, 1992, her body was found along Interstate 44 in rural Lawrence County, Missouri, between Springfield and Joplin. She had been killed. Some of her belongings were never recovered, including a 35mm camera and a Lorus musical wristwatch with a green umbrella on its face that plays "Raindrops Keep Falling on My Head."
The FBI says a tractor-trailer was reported near her car during the time she was last seen. It describes the driver, who has never been identified, as a white man between 35 and 40, over six feet tall, with dark, bushy hair. In August 2026, on the 34th anniversary, Illinois State Police said they and the FBI were working a new lead: a woman, now deceased, who investigators believe may have traveled with an unknown truck driver around that time. Police said they are re-examining about 200 pieces of evidence with modern DNA testing. No one has been charged.
What happened, in order.
Tammy leaves Evanston, IL, for Grinnell, IA. She is last seen with her car near mile marker 83 on I-80 in LaSalle County between about 3:10 and 4 p.m. A state trooper tickets the car as abandoned.13
Illinois State Police tow the car; that evening her mother reports she never reached college.1
Her body is found along I-44 in rural Lawrence County, Missouri.13
30th anniversary: the case is still unsolved and investigators again ask for tips.6
34th anniversary: Illinois State Police and the FBI announce a new lead, ask about a deceased woman who may have traveled with an unknown trucker, and say evidence is being retested for DNA.234
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