This week On The Case With Paula Zahn looks at the brutal and senseless murder of 18-year-old Traci Hammerberg from Saukville, Wisconsin, in December 1984.
Hammerberg was walking home late one night after partying with friends when she was attacked, raped, and murdered by Philip Cross. She had been walking home from Port Washington to Saukville, a distance of nearly four miles, which was a route she took regularly.
Cross dumped her body on a snowy driveway in Grafton, WI. Her semi-naked remains were discovered the following morning by the homeowner. She’d been raped, strangled, and hit in the head with a blunt metallic object.
Two different hunters had seen a car speed away from the area without headlights.
Using blood found under Hammerberg’s fingernails and semen from the crime scene, the police were able to build a DNA profile of the killer. Despite this, the identity of Cross eluded law enforcement for 35 years.
The Ozaukee County Sheriff’s Office interviewed 100s of witnesses and eliminated 400 men from their list of suspects through blood sampling and DNA analysis.
Police used genealogy to identify killer Philip Cross
Finally, there was a breakthrough in 2019 when investigators reached out to the Los Angeles FBI team, who had caught the Golden State Killer using genealogy records. When the cops fed their DNA profile of Hammerberg’s killer into the genealogy database, they zeroed in on a distant second cousin of Cross.
Investigators were able to build a family tree going back four generations, and they identified Cross as a suspect. He had died of a drug overdose in 2012, but his DNA came up as a match.
The police learned that Cross had just finished working the nightshift around the time Hammerberg was walking home. They also discovered that he’d a long rap sheet and a history of violence against women and was a drug and alcohol abuser.
More from On The Case With Paula Zahn
Follow the links to read about more horrifying murders investigated by Paula Zahn.
Last week, Paula Zahn examined another case where scientific developments in DNA sampling led to a conviction after many years. In 1987, Joseph Hatley strangled Susan Woods and left her submerged in her bathtub. Investigators were stumped for 20 years until the DNA pointed them in the surprising direction of Hatley.
Earlier this month, Paula Zahn also looked at the case of career criminal Steven Podkulski, who brutally stabbed 27-year-old Jennifer Boyd and left her to die in a storage locker.
On The Case With Paula Zahn airs Sundays at 10/9c on Investigation Discovery.