One of the shootings happened during a large party in an alley. In the other, a 12-year-old boy's family told police they were setting off fireworks when he apparently was hit by a stray bullet.

CHICAGO (AP) — The upbeat mood in a busy Chicago neighborhood known for its restaurants and nightlife quickly turned into horror late Wednesday as shots were fired at a crowd from a fast-moving vehicle, killing four people.

Gunfire from a passing car ripped into a crowd of partygoers in the River North neighborhood, the police said.