CHICAGO (AP) — A shooting at a house party early Sunday on Chicago's South Side wounded 13 people, four of them critically, Chicago police said.

The shooting stemmed from a dispute at a house party that was “given in memorial of a subject slain in April,” Chief of Patrol Fred Waller said. He said shots were first fired just after 12:30 a.m.

The victims range in age between 16 and 48 and suffered “different and various gunshot wounds to their bodies.”

Two people are being questioned, Waller said. One of them was arrested with a weapon, he said, while the other was wounded. Waller said police recovered a revolver.

Waller described three different shooting scenes at the residential location in the city's Englewood neighborhood. The shooting started inside, and then more shots were fired as people began spilling out of the house. He said shots were also fired at a third place in the vicinity.

He described the shooting as an “isolated incident.”