In an interview with The Associated Press after Hasse's death, McLelland said his deputy hadn't been involved in the Aryan Brotherhood of Texas investigation.

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Previous possible culprits mentioned included a white supremacist prison gang known as the Aryan Brotherhood of Texas, which had been targeted by a task force that included McLelland's office.

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But McLelland's office was one of numerous Texas and federal agencies involved in a multi-year investigation that led to the indictment last year of 34 alleged members of the Aryan Brotherhood of Texas, including four of its senior leaders, on racketeering charges.

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However, McLelland's office was one of numerous Texas and federal agencies involved in a multiple-year investigation that led to the 2012 indictment of 34 alleged members of the Aryan Brotherhood of Texas, including four of its senior leaders -- on racketeering charges.

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Ebel is not on the radar of the Southern Poverty Law Center, which tracks extremist groups, but the center rates the gang as one of the most vicious white supremacist groups operating in the nation's prisons, comparable to the Aryan Brotherhood of Texas.

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There are at least 425 members of the Aryan Brotherhood in Texas prisons.

ECONOMIST: Organised crime