Murder of Traci Hammerberg

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.