Investigators believe a “serial murderer and rapist” targeting sex workers is at large in the city of Detroit after the decomposed body of a third woman was found on Wednesday in a vacant house, the police chief said.

Chief James Craig said the homicides, which began in March, appeared to be related to the sex trade. He declined to “go into a lot of detail”.

Two of the three women were in their early 50s. One died of blunt force trauma, while the cause of the other deaths remains under investigation, Craig told reporters.

“We believe this is a serial murderer and rapist, and we want to alert all sex workers, particularly those who work inside vacant houses, to beware,” Craig said.

He made a public appeal for more information, especially from people who accept money for sex, although he also cautioned: “We’re not trying to create an alarm across the city.”

The first victim, Nancy Harrison, 52, was found on 19 March. Craig said the death had appeared to be a drug overdose, but the cause was changed after additional work by the medical examiner. The second victim, Trevesene Ellis, 53, was discovered on 24 May. The bodies were in vacant houses on Detroit’s east side.

Detroit has demolished about 18,000 properties since 2014 and has another 18,000 houses to go, Mayor Mike Duggan said last week.

Investigators were unable to determine the identity of the third victim discovered Wednesday because her body was badly decomposed.

“We believe all three are connected … We have no suspect description at this time,” the chief said.