Philadelphia police are investigating a shooting that claimed the lives of a woman and her stepdaughter in a pickup truck in the city's Fairhill section overnight.

Officers were called to a report of a person with a gun on the 3000 block of North Lawrence Street at about 12:05 a.m. Wednesday, police said.

When officers arrived, they found two women, ages 35 and 19, both shot in their heads in the red pickup truck, its engine reportedly still running. They were pronounced dead at the scene at 12:19 a.m.

Family members identified the victims as Lylliana Mendoza and her stepdaughter, Aslemarie Torres.

The circumstances of the deaths were not known but police said the Homicide Unit was investigating.

Chief Inspector Scott Small described the incident as a possible drive-by shooting. Witnesses reported that at least one gunman was in another vehicle when the shots were fired, he told reporters at the scene.

The preliminary investigation indicated that someone fired multiple shots into the passenger-side front door of the pickup, striking both victims, according to Small.

The motive remains unknown and no arrests have been made. Police had no description of any suspects. Numerous spent shell casings were found at the scene.

Late Wednesday morning, investigators remained at the crime scene.

A pastor said the family was involved in an upcoming peace march.

The deaths were two of three homicide cases involving female victims Wednesday, a relatively unusual occurrence in Philadelphia. Another woman died after she was stabbed and assaulted with a hammer in a Crescentville home. Police figures show that, most years, about 85 to 90 percent of homicide victims in the city are male.