A 21-year-old man was fatally shot in a triple shooting in Southwest Philadelphia on Sunday night, police said.

The victim was identified Monday as Isaiah Rankins of Nicetown.

Police responded about 8:45 p.m. to the 2500 block of South Alden Street for a report of three men who were shot and found Rankins suffering from a gunshot wound to his head. As officers put him in their patrol car to take him to the hospital, police said, a 9mm Sig Sauer handgun fell from his waistband.

Officers drove Rankins to Penn Presbyterian Medical Center, where he was pronounced dead. .

While the officers were driving to the hospital, police said, they were notified by police radio that two other victims from the same shooting were taken by private vehicles to the Hospital of the University of Pennsylvania. A 25-year-old man with a gunshot wound to his stomach and a 21-year-old man suffering from multiple gunshots wounds to his body were in critical condition at HUP, police said.

Police said they were seeking a 19-year-old man as a possible shooter in the case. No arrests were reported.