Traci Hammerberg, 18, was raped and killed while walking home in Ozaukee County, Wisconsin, on December 15, 1984. The case remained unsolved for 35 years until forensic genealogy identified Philip Cross, a Wisconsin man who had died in 2012, as her killer.
Traci Lynn Hammerberg was born March 7, 1966, in Milwaukee to Judy Klabunde and Harlan Hammerberg. Her family moved to Saukville, Wisconsin, around 1976, where she attended Port Washington High School. On the night of December 15, 1984, Hammerberg left a house in Saukville where she had been babysitting to walk to a grocery store to meet friends. The group drove to Quade's Tavern in Port Washington, and she told the bartender she was headed to a party in Grafton. According to reports, Hammerberg and her friends played a drinking game and smoked marijuana at the party before she left to walk home alone around 12:30 a.m., a 3.7-mile route along Wisconsin Highway 33.
Hammerberg was raped, strangled, and died of head injuries. Her partially clothed body was found on a snowy driveway on Maple Road in Grafton by Dan Sieracki early Saturday morning. Investigators with the Ozaukee County Police Department initially could not determine whether she had been killed at the site where her body was found or moved there afterward. Authorities were also unable to immediately identify the object used to inflict her head injuries, describing it only as something that could range "from a stick to a baseball bat"; it was later determined to be metallic. Neighbors in the wooded area north of Grafton reported not seeing or hearing anything unusual, though two hunters separately reported seeing a car speeding away from Maple Road without its headlights on.
The investigation was led by the Ozaukee County Sheriff's office, which received support from the Wisconsin Department of Justice's division of criminal investigation. An FBI Behavioral Analysis Unit assisted in developing a criminal profile. Investigators interviewed hundreds of witnesses over the years, and more than 400 men were eliminated as suspects through blood typing and DNA analysis.
A year after Hammerberg's death, Wendy Smith, a friend and former classmate, was also found dead; her death was ruled a homicide while the cause was investigated.
In March 2019, investigators began searching genealogy databases using a DNA profile built from blood recovered from underneath Hammerberg's fingernails and semen recovered at the crime scene. Investigators reached out to the Los Angeles FBI team that had previously helped solve the Golden State Killer case for expertise with forensic genealogy technology. Through this process, investigators identified a second cousin of the suspect and ultimately identified Philip Cross, a Wisconsin man, as Hammerberg's killer. Cross had died in 2012 of a drug overdose and was never charged, having died before the identification was made.
Grafton, Wisconsin (body recovery site); attack occurred along Wisconsin Highway 33 between Port Washington and Grafton
Case status
solved
Case timeline
1966-03-07
Traci Lynn Hammerberg is born in Milwaukee to Judy Klabunde and Harlan Hammerberg.
1976
The Hammerberg family moves to Saukville, Wisconsin, where Traci attends Port Washington High School.
1984-12-15
Hammerberg leaves a babysitting job, goes to a party in Grafton, and is raped and killed while walking home along Wisconsin Highway 33; her body is found on Maple Road.
1985
Wendy Smith, a friend and former classmate of Hammerberg, is found dead; her death is ruled a homicide.
2019-03
Investigators begin searching genealogy databases using a DNA profile developed from crime scene evidence.
2019
Philip Cross is identified as Hammerberg's killer through forensic genealogy; Cross had died in 2012.
Best coverage
Titles and descriptions are the creators’ own and may not reflect current legal status; see the dossier above for sourced case facts.
VIDEO
Creator
Bloodline Detectives - Episode 2 - Murder in the Snow
People
James Johnson
LAW ENFORCEMENT
Ozaukee County Sheriff who provided information on the case.
Traci Lynn Hammerberg
VICTIM
18-year-old raped and killed on December 15, 1984, in Ozaukee County, Wisconsin.
Philip Cross
CONVICTED
Identified in 2019 through forensic genealogy as Hammerberg's killer; had died in 2012 of a drug overdose and was never charged or tried.
Roles reflect public records and court outcomes at the time of writing — supporting citations are on file under Sources.
Traci Hammerberg, 18, was raped and killed while walking home in Ozaukee County, Wisconsin, on December 15, 1984. The case remained unsolved for 35 years until forensic genealogy identified Philip Cross, a Wisconsin man who had died in 2012, as her killer.
Where did the murder happen?
Grafton, Wisconsin (body recovery site); attack occurred along Wisconsin Highway 33 between Port Washington and Grafton.
Who was convicted?
Philip Cross (Identified in 2019 through forensic genealogy as Hammerberg's killer; had died in 2012 of a drug overdose and was never charged or tried.).
When a file you follow changes — a new development, a correction, fresh coverage — the Dispatch is how you hear about it.
The Casepin Dispatch
A calm weekly briefing from the archive — one case worth understanding, meaningful updates to files you follow, and the best new coverage. You’ll also get the one-time note when the apps land. No gore, no rumor, no drip.
