LOS ANGELES (AP) — Federal authorities have opened a civil rights investigation into whether Los Angeles County sheriff’s deputies engaged in a pattern of abuse of inmates.

The Los Angeles Times reports the Justice Department sent a letter to county officials this week, saying federal authorities have become increasingly concerned about allegations that deputies brutalized inmates in the nation’s largest jail system.

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The investigation would be conducted separately from the FBI’s ongoing criminal probe into allegations of excessive force and other misconduct at the jails. That investigation has been under way since at least 2011.

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A spokesman for Sheriff Lee Baca said the department would cooperate with the new federal probe.

Steve Whitmore noted that the department has also made significant reforms in an effort to deal with excessive force by jailers.

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