By CBS 2 Chicago Staff

CHICAGO (CBS) — Police were searching for an assailant Sunday night after a woman was sexually assaulted in an alley in Lakeview.

At 3:45 a.m. Sunday, the 29-year-old woman was walking west in the 1000 block of West School Street when a man grabbed her from behind, said he had a gun, and forced her into an alley where he sexually assaulted her, police said.

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The suspect then fled east on School Street on foot.

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The assailant had a black nylon covering his head, police said.

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Anyone with information was asked to call Area Three Detectives at (312) 744-8261.

CBS 2 Chicago Staff