PHILADELPHIA (CBS) — Philadelphia police are investigating a home invasion that sent an elderly man to the hospital.

The incident happened around 10:30 Saturday night in the 2000 block of Church Lane.

Police say the 78-year-old victim’s grandson left the door unlocked when he went to get coffee. The victim told police that the suspect walked into the home, struck him over the head with the gun, and then stole his wallet.

The victim was taken to Einstein Medical Center where he was treated for a laceration to the head.

The suspect is described as a thin man in his early 40’s, standing 5-foot-10. Police say he was dressed in all black clothing.

Anyone with information regarding the incident is asked to call Philadelphia Police.