CHICAGO (STMW) — A northwest Indiana man has been charged with a gang-related killing in Hammond last year, and prosecutors say his mother threatened a witness on Thursday.

Anton James, 19, faces murder charges for the Oct. 28, 2014 slaying of Martin Hurtado Sr., according to a statement from the U.S. Attorney’s office in the Northern District of Indiana.

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James, a member of the Latin Kings street gang, mistook the 45-year-old Hurtado Sr. for his son Martin Hurtado Jr., a rival gang member, federal prosecutors allege.

About 9:20 p.m. that night, James shot the man once in the shoulder while he was in his backyard working on a car in the 800 block of South State Street, Hammond police said at the time. He died at a hospital that night.

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About 9:20 a.m. Thursday—the day of James’ court appearance—his mother Dalia Guerrero told a witness she knew what the person looked like, where they live and “to watch their back” in order to influence their testimony, prosecutors said.

Guerrero, a 39-year-old Merrilllville resident, was arrested about noon, prosecutors said.

Hammond police and the FBI are investigating.

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(Source: Sun-Times Media Wire © Chicago Sun-Times 2015. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)