WYOMING, MI -- Police have released details describing a grisly scene in the triple homicide that killed a pregnant teen and her boyfriend last week.

Brooke Slocum, 18, was strangled to death and Charles Oppenneer, 25, was killed through unknown means, as his head was removed from his body, Wyoming Police Chief James Carmody said at a press conference Monday.

Oppenneer's head has not been located. Oppenneer's body was found near his abandoned vehicle near Gezon Park on July 16.

Investigators said Slocum was likely killed July 17, prior to her body being discovered in the trunk of suspect Brady Oestrike’s car.

Police say Oestrike, 31, killed himself after fleeing from police and crashing his car.

Emails showed Oestrike and Slocum had arranged to meet for sex on Saturday in Gezon Park, and Oppenneer was supposed to attend, Carmody said.

The two connected on Craigslist, investigators said.

A multiple day search of the home of Oestrike’s home revealed restraints suggesting Slocum was held captive there prior to her death, he said.

Carmody said it’s been a “hellish environment” for officers as they dealt with the different scenes. Investigators collected more than 400 items from Oestrike’s home, including firearms, ammunition and knives.

A number of electronics were also found in the home, along with possessions of both victims.

Carmody said a former girlfriend who used to live with Oestrike had filed a domestic assault report when she moved out in June. She made a similar report in May, but did not wish to pursue charges.

Police will continue to investigate to determine if others were involved.

Oppenneer’s family released a statement at the press conference, explaining their sympathy to Slocum’s family and requesting privacy.