Morbidology is a weekly true crime podcast created and hosted by Emily G. Thompson. Using investigative research combined with primary audio, Morbidology takes an in-depth look at true crime cases from all across the world.

21-year-old Tammy Zywicki was driving from her New Jersey home to Iowa’s Grinnel College for her senior year on the 23rd of August, 1992. Tammy was an art and history major and loved animals and James Dean. She was nicknamed “Zee” because of her penchant for “power naps.”

On that fateful afternoon, Tammy had decided to head back to college early so that she could take preseason photographs of her college sports teams for Andy Hamilton, who was Grinnell’s assistant sports information director at the time. En route to Grinnel College, Tammy dropped her brother, Darren, off at Northwestern University in Evanston before heading on her way. Darren later recalled that her car repeatedly overheated during their trip from New Jersey.

She was last spotted at the side of Interstate 80 near LaSelle in central Illinois. She was standing beside her car and several witnesses said that there was a truck parked behind her. The witnesses also recalled that they saw a man who appeared to be offering Tammy assistance with her car troubles. The man was described as being a white man of around 30 to 45 years old. He stood at 6 feet tall and had dark, bushy, collar-length hair. The truck was described as white with two brown diagonal stripes down the side.

When Tammy’s mother discovered that her daughter never arrived at Grinnell College, she called the police to report her daughter missing. The following day Tammy’s white Pontiac 1000 was found abandoned alongside westbound Interstate 80 near Utica. The locked car contained Tammy’s packed bags and her other belongings. Tammy, her car keys and her purse were nowhere to be found.

Two weeks later, a local man was walking alongside Interstate 44 near Sarcoxie, Missouri, approximately 50 miles west of Springfield, Missouri when they found the body of a young woman wrapped in a blanket. The body was extremely decomposed. While the clothes matched the description of the clothes Tammy wore on the day she disappeared, she was identified via dental records. She was around 500 miles away from where she was last seen at the side of the road. The young woman who once wrote in her high school journal that she didn’t want to suffer when she died was brutally murdered.

An autopsy concluded that Tammy had been sexually assaulted and then stabbed seven times in a circle around her heart and once in her right arm. Duct tape was placed over her mouth to muffle any screams. It was determined that she was dead up to a week before she was found. Lawrence County sheriff’s Detective Greg Brandma said that Tammy had been killed elsewhere and then dumped at the site. She had been robbed of her Canon 35mm and her wristwatch which played the tune “Raindrops Keep Falling on my Head.” Furthermore, a St. Giles Soccer Club patch was missing from Tammy’s shorts.

After the grim discovery, members of the college community gathered at Herrick Chapel in a remembrance of Tammy. “We hope some good will come out of this, including the capture of the person responsible. We don’t want him to be able to kill again,” Tammy’s family said. Investigators released a description of the man who was spotted assisting Tammy with her car troubles. They announced that he wasn’t a suspect but said he could offer assistance in their investigation.

Tammy funeral was held on the 8th of September. Over 50 mourners – some of whom didn’t even know Tammy – filed into St. John Neumann Roman Catholic Church in Mount Laurel to grieve the loss of the bubbly young woman. They remembered her as a lover of nature and a believer in life. “She was the nicest person in the world,” said Rebecca Campbell. “She was fun-loving and spirited.” Following the service, Tammy was buried in West Newtown Memorial Cemetery south of Pittsburgh, near the Roman Catholic church where her parents were married and not far from Pleasant Hill, where she was born. On her tombstone is a picture of Garfield, her favourite cartoon character.

Over the forthcoming years, there have been several suspects in the murder of Tammy. In fact, whenever a trucker was suspected in a kidnapping, sex crime or murder, they automatically became a suspect in the Tammy Zywicki case.

One suspect came to light in 1992 when James Dante Mackey, 38, a Tampa truck driver, was arrested in Indiana on charges of attempted rape. Mackey was arrested on the 31st of March outside Southlake Mall just off Interstate 65 in the northwestern part of Indiana. A woman had told police that he had attempted to rape her as she was on a pay phone. After his arrest, police found women’s undergarments and pornography in his truck. Despite rumours, investigators found no evidence that linked him to the murder of Tammy. Trucking logs and gas receipts placed him at least 100 miles from where she was slain.

At one point in the investigation, authorities focused on Bruce Mendenhall, a southern Illinois trucker who was convicted in 2007 of the murder of 25-year-old Sara Hulbert. While incarcerated, he confessed to murdering six more women. Mendenhall primarily targeted young sex workers that he picked up in his truck. Despite the fact that Tammy wasn’t his typical profile type, authorities considered the chance that he killed Tammy. Nevertheless, they never could tie him to the murder.

Another one of the main suspects throughout the years was Lonnie Bierbrodt, a truck driver with a history of violent crime. An anonymous tipster described somebody matching his description as the man who was spotted in the vehicle behind Tammy at the side of the road. In addition, Lonnie’s wife was said to own a wristwatch eerily similar to Tammy’s missing one. Tammy’s mother, Joanne, and former Illinois State Police investigator, Marty McCarthy, consider him the most promising lead. Nevertheless, prosecutors resisted charging him due to the fact that there wasn’t enough evidence to take the case before a grand jury. He passed away in 2002.

Tammy’s mother, Joanne, declared that she wasn’t happy with the early investigation by the Illinois State Police. “As the years go by, it’s very irritating. There were so many blunders in our case. They lost the case in the first few days,” she said. She said that police didn’t immediately release the description of the truck that was believed to be involved in Tammy’s disappearance. She also said that it took authorities more than 24 hours to enter Tammy’s car into the police’s central computer.

In 2017, authorities issued a press release in which they asked the public for help in identifying the driver of the vehicle who was spotted seemingly assisting Tammy with her car troubles. Authorities had hoped that by releasing a description of the man and his truck, it could refresh someone’s memory. During the press release, authorities declared that the case is still open and that they are actively pursuing new investigative strategies that could lead to a crack in the case.

“No one has forgotten Tammy – not her family, her high school and college friends, and certainly not law enforcement. I am very motivated to find her killer,” said Special Agent Amanda Becker. With forensic science constantly advancing, authorities hope that evidence found at the scene – the blanket and duct tape as well as other significant items – could one day reveal the killer’s DNA.

The idea that a predator prowling the nation’s highways posing as a Good Samaritan truly is a chilling thought and as of today, the murder of Tammy Zywicki still remains unsolved. A reward of up to $50,000 has been offered for information leading to identification of the individual responsible.

If you have any information in the unsolved murder of Tammy Zywicki, please call: ( 815) 726-6377.