The 2018 disappearance of twenty-year-old University of Iowa student Mollie Tibbetts made national headlines. Her body was found one month later in a cornfield.

Twenty-six years earlier, another Iowa coed, twenty-one-year-old Tammy Zywicki, disappeared. On September 1, 1992, nine days after she was last seen, her body was found in southwest Missouri.

Both Mollie Tibbets and Tammy Zywiciki attended colleges in Iowa. Each was stabbed to death. Neither knew her assailant. One major difference, however, separates the brutal murders of the two young women.

In 2021, a man was convicted of the murder of Mollie Tibbetts and sentenced to life in prison. After over thirty years, though, no one has been charged with the murder of Tammy Zywicki.

Tammy Zywikci

Tammy Zywicki hailed from New Jersey, but she and her brother Daren headed to the Midwest for their educations. Tammy was enrolled at Grinnell College in Grinnell, Iowa, fifty miles northeast of Des Moines. Daren attended Northwestern University in Evanston, Illinois.

On Sunday, August 23, 1992, Tammy drove her brother to his dorm room. She departed Evanston that afternoon en route to Grinnell where her classes for the 1992-93 school year began the following day.

The distance between the two colleges is just under three-hundred miles, and Tammy planned to arrive in Grinnell that evening.

Gearing for Classes

In the late afternoon of August 23, an Illinois State Trooper found a 1985 Pontiac T1000 bearing New Jersey license plates abandoned at the side of Interstate 80 near LaSalle, Illinois, approximately one-hundred miles southwest of Evanston. He assumed the car had mechanical difficulties and that the occupant had pulled to the side of the road in an effort to fix them.

The following day, after finding the car still sitting along the side of the Interstate, the Illinois State Police towed the vehicle.

Illinois police soon received a call from JoAnn Zywicki of Marlton, New Jersey. The concerned mother told them her daughter Tammy had not arrived for classes at Grinnell, and her roommates reported she had not checked into her dorm. The abandoned broken down car was confirmed as Tammy’s.

Tammy’s Car

A sinister scenario was unfolding. A college girl was missing with her car found along the side of a busy Interstate. Authorities feared the worst.

Nine days later, those fears were confirmed.

A No-Show for Classes

On September 1, Tammy’s body was found in a ditch along the Interstate 44 westbound on ramp just east of Sarcoxie in Lawrence County, Missouri, twenty-two miles east of Joplin. She was bound with duct tape and wrapped in a red blanket.

An autopsy determined that in addition to being raped, Tammy had been stabbed eight times: seven times in and around her heart and once in her arm.

Body Found

The location of Tammy’s remains was approximately five-hundred miles from where her abandoned car had been found nine days earlier.

Tammy’s Terrible Trek 

Several motorists traveling along Interstate 80 on August 23 recalled seeing Tammy standing near her car at mile marker 83 between LaSalle and North Utica in north-central Illinois. These sightings were all believed to have been between 3:10 and 4:00 p.m.

The witnesses also remembered seeing a white tractor-trailer parked near Tammy’s car. It was described as five-axle with rust-colored diagonal stripes on the trailer and cab. A logo was juxtaposed over the stripes, but no one could recall from which company.

One witness recalled seeing Tammy standing beside her car on the shoulder of the Interstate. The car’s hood was open and an agitated Tammy appeared to be struggling to fix the problem. A man was standing near the vehicle, watching as Tammy played mechanic. He was described as appearing thirty-five to forty years old, white, and at least six feet tall with dark, bushy hair.

A September, 1992, Des Moines Register article stated the witness who reported seeing the man was a male trucker, but later reports say the witness was a female nurse.

Clues Come In,

But None Pan Out

The witness also reported that a woman came for a blood test to the medical facility where the nurse worked that same day of August 23. The patient said her husband was a trucker and that he had recently given her a musical watch. The description matched that of a Lorus watch Tammy possessed when she left Evanston, Illinois.

Tammy’s watch, her Canon Camera, and a soccer club patch she was believed to also have had with her, were never found.

A Watch and Patch Similar to Ones Belonging to Tammy

Several suspects have been named in the murder of Tammy Zywicki. One of them is long-haul truck driver and possible serial killer Bruce Mendenhall. In 2007, he was arrested for killing twenty-five-year-old Sara Hulbert in Tennessee. Subsequently, his truck was examined and the blood of several murdered or missing women was found in it. None of the blood, however, was determined to be Tammy Zywicki’s.

Mendenhall was convicted of Sara Hulbert’s murder in 2010. He has also been charged with the murders of three other women at truck stops in Indiana, Tennessee, and Alabama. In addition, he is a suspect in the murders of women in New Mexico, Texas, Oklahoma, Georgia, and his native Illinois. Mendenhall is imprisoned in Tennessee.

One source says Mendenhall has been ruled out as a suspect in Tammy’s murder because it was proven he was not in the Midwest at the time. Other sources, however, say he has not been officially cleared.

Bruce Mendenhall and Sara Hulbert

The name, however, that is mentioned most frequently as the possible killer of Tammy Zywicki is that of another long-haul trucker, Lonnie Bierbrodt. He had been sentenced to three concurrent twenty-year terms in prison for two armed robberies and an attempted murder before being paroled in 1990.

In addition to his violent past, many investigators consider Bierbrodt the prime suspect in Tammy’s murder because he had been visiting family who lived only a few minutes from where she was last seen in Illinois, and he lived near where Tammy’s body was discovered in Missouri. In addition, the red blanket covering Tammy’s body bore a Kenworth logo; Bierbrodt drove a Kenworth truck which he had steam-cleaned and sold shortly after Tammy’s murder.

Des Moines Register articles state authorities identified Bierbrodt as the man seen with Tammy, that he was questioned, and that he provided blood and hair samples.

Bierbrodt died in 2002 at age forty-one.This is the only picture I could find of him; it looks like a high school yearbook photo.

 

Lonnie Bierbrodt

Several newspaper articles state that the nurse at the medical facility identified the man she saw as Lonnie Bierbrodt, and that police determined he was the man seen with Tammy along the side of the Interstate.

Robert Kotlarek is a member of my Facebook group and also operates the Facebook group “Who Killed Tammy Zywicki.” He clarifies this point below. This information was told to him by Martin McCarthy, the now-retired lead detective investigating Tammy’s murder, and Tammy’s mother JoAnn:

“The “Bushy haired” semi-truck driver has gotten conflated with Bierbrodt over the years. Like the old “telephone” game children play (or once played), the information has gotten distorted. The nurse witness reported seeing a green pick-up truck and a man with “short brown hair” that was possibly “thinning on top”. She later (December of 1992) thought that Lonnie was the man she saw on the side of the road. Bierbrodt’s wife Carrie DID own a blue pick-up that WAS sold after Tammy was murdered. The nurse witness never mentioned a semi-truck in her initial interview with police, and as far as we can tell Bierbrodt was not driving a semi in Illinois on 23 August 1992. So basically, the “bushy haired” truck driver and the nurse witness’ description of the man that matched Lonnie Bierbrodt are from (at least) two separate accounts.”

Join Robert’s Facebook group “Who Killed Tammy Zywicki.

 

https://www.facebook.com/groups/71031476920/ 

 

Was Bierbrodt the Man Seen With Tammy?

On June 7, 1992, nine weeks before Tammy Zywicki’s murder, nineteen-year-old Suzie Streeter, eighteen-year-old Stacy McCall, and Suzie’s forty-seven-year-old mother, Sherrill Levitt, disappeared from Sherrill’s Springfield, Missouri, home, approximately fifty miles from where Tammy’s body was found.

With the exception of a broken porch light, there were no signs of a struggle. The women’s cars and purses and other personal belongings were left at the house. The “Springfield Three” have never been found.

Although many speculate there may be a connection between the disappearances of the Springfield Three and the murder of Tammy Zywicki, no link has been established.

The Missing “Springfield Three”

Left to Right: Suzie Streeter, Stacy McCall, Sherrill Levitt

Convicted kidnapper and robber Robert Cox told journalists in 1997 that he murdered the Springfield Three. Cox, a dishonorably discharged Army veteran who is also a suspect in a Florida murder, confidently claimed the trio’s remains will never be found. Authorities are divided on whether he was involved in the women’s disappearances or if he is making a false confession.

Cox is imprisoned in Texas. I did not find a source stating if he was or ever has been a suspect in Tammy’s murder.

Robert Cox

Fifty-nine-year-old Clark Baldwin was arrested in Waterloo, Iowa, in May, 2020. Authorities say DNA evidence connects him to three murders committed during the 1990s.

Baldwin is charged in Tennessee with the 1991 murder of Pamela McCall, a thirty-two-year-old pregnant woman from Topping, Virginia. He is also charged with the murders of two unidentified women whose bodies were found in Wyoming in 1992. They have been dubbed “Bitter Creek Betty” and “I-90 Jane Doe.”

In the 1990s, Baldwin was a cross-country driver for Marten Transport and had lived in both Nashua, Iowa, one-hundred miles north of Grinnell College and Springfield, Missouri, approximately fifty miles from where Tammy’s body was found.

Baldwin is being held without bond in the Maury County, Tennessee, jail in preparation for his trial in the murder of Pamela McCall. Authorities are investigating his possible involvement in several additional murders but say he has been ruled out as a suspect in the murder of Tammy Zywicki.

Clark Baldwin

Alleged Murder Victims of Clark Baldwin

Left to Right: Pamela McCall, “Bitter Creek Betty” and “I-90 Jane Doe.”

 

The FBI still features Tammy Zywicki on its website and continues to offer a $50,000 reward for information leading to the identity of her killer. In addition, a separate $100,000 reward is offered by an anonymous person or group from Tammy’s hometown of Marlton, New Jersey.

The FBI has DNA evidence obtained from Tammy’s body which agents believe will lead to the killer’s identity.

If you have any information you believe may be related to the murder of Tammy Zywicki, please contact the Illinois State Police at (815) 726-6377, or the Chicago FBI Field Division Office at (312) 421-6700.

Still Publicized 

https://www.findagrave.com/memorial/20795642/tammy-jo-zywicki 

SOURCES:

• Associated Press

Cedar Rapids Gazette

• Des Moines Register
• FBI
• Grinnell College
• Illinois State Police
• Iowa Cold Cases
• Missouri State Police
• Sioux City Journal
• WHO-TV Channel 13 Des Moines