A shooting early Friday in San Francisco’s Mission District left a 32-year-old man with life-threatening injuries, according to police.

Around midnight, officers responded to a report of a ShotSpotter activation in the 1300 block of Potrero Avenue. There, officers found spent shell casings. They also learned a victim from the shooting had already went to the hospital for his critical gunshot injuries.

No arrest was made in the shooting and police haven’t provided a description of shooter. The investigation remains ongoing and anyone with information is encouraged to contact the Police Department’s anonymous tip line at (415) 575-4444 or to send a tip by text message to TIP411 with “SFPD” at the start of the message.