PHILADELPHIA (CBS) — Philadelphia police are investigating a double homicide in the city’s Oxford Circle section after two women were found shot dead inside a home.

A 66-year-old mother and her 42-year-old daughter were found with gunshot wounds to their heads inside a home in the 1200 block of Greeby Street, just before 11:30 p.m. Monday.

Police say a mother, who was in a wheelchair, was found on the first floor and the daughter was found on the second floor. Both were pronounced dead at the scene.

Police found a gun inside the home but it’s not clear if it’s the murder weapon.

The daughter’s 39-year-old boyfriend who lives inside the home was taken for questioning.

Philadelphia Police Capt. John Ryan says they think the boyfriend is in the one behind the shooting.

“The investigation has developed and that’s where it is pointing at this point. There’s a lot of work to be done and a lot of things to be confirmed,” Ryan said.

Police do not have a motive yet for the shooting.

The victims’ names have not yet been released.