Highway crews in Walworth County discovered the remains of two women inside suitcases, on June 5.
Authorities accuse the suspect of hiding the bodies for months. Prosecutors on Thursday charged 52-year-old Steven Zelich of West Allis with two counts of hiding a corpse.
Investigators say the former police officer met his victims online, bound and killed them and then carried their remains in his vehicle for months.
According to the criminal complaint, Zelich killed one woman more than a year ago, and the second victim, in November. She has been identified as 37-year-old Laura Simonson of Farmington, Minnesota. Investigators say Farmington was likely killed in a hotel room in Rochester, Minnesota. She and the suspect had reportedly checked into the hotel together in November, but only he was seen leaving the following day. Her family had reported her missing.
The second victim has not yet been identified.
On Wednesday, detectives wearing hazmat suits removed bags of items from the suspect's apartment in West Allis, and a refrigerator.
Police say Zelich was a West Allis patrol officer from 1989 until 2001, when he resigned for reasons that have not been made public. In more recent times, he has been working as a private security guard.
Workers discovered the suitcases along a rural road in the Town of Geneva - about a 50-minute drive southwest of Milwaukee.