Detroit police say three of four women recently found dead in car trunks had promoted themselves as escorts through the same website.
Chief Ralph Godbee said Monday the deaths could be connected but cautioned that police were "stopping short" of calling it the work of a serial killer.
Police discovered the badly burned bodies of two women in a car trunk early Sunday. The bodies of two other women were found just blocks away in another car trunk on Dec. 19. All four women were in their 20s. The causes of death remain under investigation.
Godbee said three of the four victims had profiles on a website used to buy and sell things but that also carries personal ads.
Police have said they don't yet have any suspects.