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An Oklahoma man who tried to blow up a bank in what authorities described as an anti-government plot was sentenced to 25 years in federal prison Monday.

In a statement, the U.S. attorney for western Oklahoma, Timothy Downing, said the prosecution of Jerry Drake Varnell, 26, held him accountable for an effort to copy the deadliest act of domestic terrorism in American history.

Jerry Drake Varnell in an undated photo. Oklahoma Department of Corrections / via Reuters

Prosecutors had accused Varnell of trying to detonate a 1,000-pound ammonium nitrate bomb in an alley beside BancFirst in downtown Oklahoma City in 2017. The 1995 bombing of the city's Alfred P. Murrah Federal Building killed 168 people and injured hundreds more.

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Varnell's arrest was the result of a monthslong domestic terrorism investigation led by the FBI. He was convicted in February 2019 of trying to use a weapon of mass destruction and other crimes.

Varnell had described the bombings as retaliation for "freedoms" that have been taken away from Americans, court documents say. The documents said he subscribed to the ideology of the Three Percenter group, part of the extremist militia movement.

The national group — which the Southern Poverty Law Center, a nonprofit hate-group monitoring organization, has described as anti-government — condemned Varnell.

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Defense attorneys claimed that Varnell was entrapped, and his parents testified that he is a paranoid schizophrenic, even though he was found mentally competent to stand trial, The Associated Press reported.

A defense lawyer, Vicki Behenna, filed a notice of appeal Monday. She did not immediately respond to a request for comment.