A 21-year-old man is in life-threatening condition after he was struck by gunfire early Sunday morning in the Mission, police said.

Police were alerted to a shooting at 18th and Dolores streets when Shotspotter gunshot detection technology activated in the area around 1:22 a.m., police said. Officers found shell casings at the scene but no victim.

Sometime later, the wounded man showed up at the San Francisco General Hospital emergency room with a gunshot wound to his chest, police said.

He was shot with a handgun, police said. There are no suspects in the case.

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