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A prison reform advocate was arrested and accused of breaking into a Tennessee jail and drawing up his own blueprints of the facility based on his break-ins, authorities said Monday.

Alex Friedmann, 50, the managing editor of Prison Legal News, was arrested Saturday at the soon-to-be-completed Downtown Detention Center in Nashville, the Davidson County Sheriff's Office said in a statement.

Alex Friedmann, a criminal justice advocate, was released on bond after being charged with attempted burglary, evidence tampering and possession of burglary tools. Davidson County Sheriff's Office

Sheriff's lieutenants in the jail's control room first spotted "a set of keys with a ring that looked different from the others" on Dec. 30, and an audit "confirmed two facility keys were missing," according to the statement.

Investigators identified a suspect after reviewing surveillance video and finding a man dressed like a construction worker entering the "key control room," the sheriff said.

A man resembling that suspect, later identified as Friedmann, was arrested Saturday at the jail carrying bolt cutters and his own map of the facility, authorities said.

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It's believed Friedmann had "previously entered the building under false pretenses on at least three other occasions," according to investigators.

"He had schematics that he had created on his own" from knowledge gleaned from the earlier break-ins, sheriff's spokeswoman Karla West said in an interview Monday. "For security purposes, you'd never provide something like that to the public."

The two missing keys have still not been found — and one of them opens 85 locks, according to West. Jailers may have to change as many as 100 locks before the 762-bed facility opens in late February.

Friedmann has been charged with attempted burglary, evidence tampering and possession of burglary tools.

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"The seriousness of Mr. Friedmann's charges cannot be ignored," Sheriff Daron Hall said in a statement. "His actions have placed the safety and security of our entire community in peril, not to mention DCSO and inmates."

Paul Wright, executive editor of Prison Legal News, said in an interview that Friedmann never told him about any plans to break into the Nashville jail — and that he would not have approved of any such tactics.

"No, absolutely not," Wright said. "We don't condone any illegal activity. As a legal organization, we advocate for the use of the court system and political process to advocate for change."

Friedmann is still managing editor of the Florida-based publication, and Wright said he'd withhold judgment as the prosecution plays out.

Prison Legal News describes itself as dedicated to the "review and analysis of prisoners' rights, court rulings and news concerning criminal justice-related issues."

Friedmann said Monday that he hadn't yet hired an attorney and declined to comment.