Police are investigating an overnight shooting in the Mantua section of West Philadelphia, which left four people injured, one critically. An unidentified gunman opened fire near 39th and Melon at around 11:15 p.m. Sunday, just as a block party was winding down nearby. Four people were taken to the hospital with gunshot wounds. One victim, a 24-year-old man, was shot multiple times and was listed in critical condition, according to a police report.

The other three victims, an 18-year-old man and two 21-year-old men, were listed in stable condition, according to police.

A total of 31 shell casings were recovered at the scene of the shooting, according to police.

Police say the gunman fled the scene in a vehicle. The motive is currently unknown and no arrests have been made.