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In 34 years, investigators in Illinois have never zeroed in on a person of interest in the murder of Tammy Zywicki, a college student heading from New Jersey to Iowa.
They believe the person who killed her was a male truck driver with brown hair, but the description doesn’t run much deeper despite 37 eyewitnesses.
Now investigators believe Theresa Belenske, a woman they say spent time drifting around Southern California, may provide clues that have long eluded authorities.
Investigators say Zywicki dropped her brother off at Northwestern University on Aug. 23, 1992, before beginning a trip west to start her senior year at Grinnell College in Iowa. Her car was experiencing mechanical problems during the trip.
Eight days later, investigators found Zywicki’s body, redressed, bloodied and beginning to decompose on the side of a trucking route in Missouri.
Investigators say her body had been dumped more than 500 miles from where she’d pulled over when her car engine overheated.
“The way that she was discarded, just kind of wrapped up in a blanket. There wasn’t a lot of any intent by the suspect to hide her,” Illinois State Police Lt. Ryan Kaney, who has led the investigation since 2016, said.
That crime scene blanket, and DNA discovered on it, could now be crucial.
Last month, on the 34th anniversary of Zywicki’s murder, investigators announced their first break in years.
“We ended up identifying our first known individual outside of Tammy. Her name was Theresa Vega, or Theresa Belenske,” Kaney said.
Investigators used artificial intelligence to generate a photo that they believe resembles what Belenske looked like in 1992. Described as a wandering soul, investigators say Belenske spent time in Southern California in the mid-80s.
She had connections in Oceanside, Vista, Fontana, Pomona and San Bernardino.
“We’ve talked to family members. We know that this Theresa would often just disappear for years at a time,” Kaney said. “We know that she was riding with truck drivers, hitchhiking, and so we’re really trying to appeal, specifically, to your area in Southern California to anyone who may have known this Theresa Belenske or Theresa Vega.”
Time ran out for investigators to talk to Belenske. She died in 2014 when she was 54.
Investigators are now looking for anyone in Southern California who knows anything about her. They believe she could still be their best source to finding the truck driver they believe murdered Tammy Zywicki.
“She’s one degree of separation,” Kaney said when asked what Belenske’s connection to Zywicki may be.
“We know, through our DNA testing program, we developed that her profile was in our crime scene,” Kaney added. “We’re not quite sure how she got there. We do know, however, that she likely, at some point, had interaction with our suspect.”
“If that gives some clue to be able to backtrack to somewhere,” said Dean Zywicki, Tammy’s older brother. “I think we’re just in a time period where time is running out to do something,” he said.
Tammy Zywicki’s unsolved murder has haunted her family since 1992. Their parents died without ever knowing who killed their only daughter.
Investigators are asking anyone who might recognize Theresa Belenske or know anything about her to send what they can to Illinois State Police at [email protected] or your local FBI.
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