Chester police are treating as suspicious the deaths of three adults and a child whose bodies were in a city apartment on Saturday night.

A call from a relative of the victims sent police to the second-floor apartment on Keystone Road at about 7:30 p.m., Chester City Police Chief Floyd C. Lewis said.

After police were able to get in, they found the bodies of a man and two women, all of whom appeared to be in their 20s, and a toddler, he said. There was no sign of trauma on the victims, Lewis said.

Authorities said there was no sign of forced entry and there was no indication the apartment had been ransacked. Police originally suspected that the deaths were due to carbon monoxide, but fire department crews were able to rule that out.

"The people were in different rooms, so we're still investigating," Lewis said. The bodies were found in a living room and a bedroom.

Police have classified the deaths as suspicious but have not ruled out anything other than carbon monoxide. Lewis said authorities hope to have more answers after the medical examiner does autopsies on the victims, whose names have not been released.