By Al Novack

PHILADELPHIA (CBS) — Authorities are investigating a shooting that wounded four men in what police are calling a drug-related home invasion in Southwest Philadelphia early Thursday morning.

Investigators say a group — estimated at about six people — broke through a front door of a residence located at 7400 Medrick Place in the city’s Eastwick section around midnight and shot three men.

The three victims, ages 23, 29 and 30, were all listed in stable condition at the Hospital of the University of Pennsylvania.

A woman who was also inside the house was not injured.

A short time after the shooting victims were admitted, police say a fourth man, claiming to have been shot near 58th and Kingsessing Streets, showed up at the emergency room. But police believe he had actually been shot inside the residence that was the scene of the home invasion.

According to police, the home was being used to package and distribute marijuana, a large amount of which was found inside the residence.