CHICAGO (CBS) — An emotional ceremony on Wednesday paid tribute to fallen Chicago Police Officer Brian Strouse.

Officers Wednesday evening took part in a memorial roll call in Strouse’s honor at 18th Place and Loomis Street in Pilsen, where Strouse was shot and killed on June 30, 2001, 20 years ago Wednesday.

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As recounted by the Chicago Police Memorial Foundation, Strouse, 33, and two partners were working as plainclothes tactical officers at 2 a.m. that morning as they conducted surveillance of gang activity. Strouse was walking in an alley when Hector Delgado, then 16 and working “security” for the Ambrose Nation street gang, spotted Strouse, the foundation recalled.

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Strouse ordered Delgado to drop his gun, but Delgado fired and Strouse was killed, the foundation recalled.

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Delgado was initially sentenced to life in prison.

CBS 2 Chicago Staff