Illinois State Police and the FBI announced a new lead Saturday, Aug. 22, in the 1992 murder of Tammy J. Zywicki, a 21-year-old Evanston woman who was kidnapped and stabbed to death while driving to college in Iowa.
Investigators identified Theresa "Teri" Belenske as a person of interest. Belenske, whose maiden name was Vega, was known to hitchhike and may have been traveling with an unidentified truck driver suspected in the case, according to Illinois State Police. She is not a suspect.
Belenske would have been 32 at the time of Zywicki's death. She died in 2014 at age 54.
What happened in 1992
Zywicki disappeared on Aug. 23, 1992, after dropping off her brother at Northwestern University and heading west on Interstate 80 toward Grinnell College in Iowa. An ISP trooper found her abandoned 1985 white Pontiac T1000 near mile marker 83 in LaSalle County later that day. A semi-trailer truck and its driver had been spotted near the car between 3:10 and 4 p.m.
The driver was described as a white man between 35 and 40 years old, over 6 feet tall, with dark, bushy hair.
He has never been identified.
Zywicki's body was found Sept. 1, 1992, along Interstate 44 in rural Lawrence County, Missouri, CBS News Chicago reported. She had been stabbed to death and sexually assaulted. Investigators believe she was killed elsewhere and her body was driven across Illinois and Missouri before being dumped.
New DNA work and a $50,000 reward
ISP and the FBI are examining approximately 200 pieces of evidence and retesting items with modern DNA technology, ABC7 Chicago reported. In 2024, investigators said they had recovered DNA that was previously considered unstable and were pursuing leads from usable samples.
The FBI is offering up to $50,000 for information leading to the identification of the person or people responsible for Zywicki's murder.
Dean Zywicki, Tammy's older brother, told Shaw Local the family was not given advance notice of the announcement but welcomed the development. "It is very encouraging to see that there is still activity on this case," he said.
He said he was unaware whether there was a connection between the DNA evidence and Belenske.
What investigators want
ISP agents are seeking information about Belenske from the late 1980s through the mid-1990s. She had ties to several California cities, including Oceanside, Vista, Pomona, San Bernardino and Fontana. ISP released a 2009 photograph of Belenske and an AI-generated image of what she may have looked like in 1992.
Several of Zywicki's personal belongings remain missing, including a Canon 35mm camera, a Lorus-brand musical wristwatch that played "Raindrops Keep Falling on My Head" and a red-and-white soccer patch marked "St. Giles Soccer Club, Greenville, SC."
Anyone with information can submit a tip anonymously at isptips.illinois.gov or call 1-800-CALL-FBI.
