Tammy Zywicki Murder: Still Unsolved 25 Years Later

JOLIET (CBS) -- This week marks 25 years since college student Tammy Zywicki was last seen alive.

Investigators have not given up on solving her murder, continuing to explore new leads, examining 200 items of evidence, and retesting items with modern DNA technology.

Zywicki was reportedly last seen with her car on Interstate 80 at mile marker 83 in LaSalle County, between 3:10 and 4:00 p.m. on Aug. 23, 1992. She departed Evanston for college in Grinnell, Iowa, where she was expected to arrive that evening.

Later that day, her car, a 1985 White Pontiac T1000, was found by an ISP Trooper and marked as being abandoned.

The next day, Zywicki's mother contacted the ISP and advised that her daughter had not arrived at college.

Her body was located on Sept. 1 along Interstate 44 in rural Lawrence County, Missouri, which is located between Joplin and Springfield. She had been stabbed to death.

A truck tractor semi-trailer was seen near Zywicki's vehicle during this time period. The truck driver was described as a white male between 35 and 40 years-of-age, over six feet tall, with dark, bushy hair.

Some of Zywicki's personal property are known to be missing, including a Cannon 35mm camera and a Lorus brand musical wrist watch which played the tune "Raindrops Keep Falling On My Head," with a green umbrella on its face and a green band.

Also taken from Zywicki was a red and white soccer patch monogrammed with "St. Giles Soccer Club, Greenville, South Carolina."

The FBI is offering a reward of up to $50,000 for information leading to the identification of the individual or individuals responsible for this crime.

Anyone with information is asked to contact the ISP at (815) 726-6377, or the FBI Chicago Field Division at (312) 421-6700. Callers can remain anonymous.