A 19-year-old is dead and an 18-year-old injured after a violent night in South Philadelphia, according to Philadelphia officials.

Authorities said a small group of men approached the victims shortly before midnight Sunday and started shooting near 16th and Catherine streets.

Police said at least 31 rounds were fired. Stray bullets were found inside parked cars and even a neighboring home, investigators said.

At least one stray bullet flew through a second-floor wall, hit a small couch and struck a mattress where a resident would normally be sleeping.

“When they heard the gunshots … they jumped to the ground,” Philadelphia Police Chief Inspector Scott Small said. “While they were laying on the floor, they heard continued gunshots.”

The 19-year-old victim was shot in the head, torso and both arms, police said. He was taken to a hospital but died there a short time later.

The 18-year-old victim was shot once in the left leg but managed to run away. He was later taken to a local hospital and remained there Monday in stable condition.

Several witnesses told investigators they saw three people running onto Fitzwater Street from the corner where the shooting happened. Police are reviewing surveillance video as in the investigation continues.