LOUISVILLE, Ky. >> The man accused of tackling U.S. Sen. Rand Paul in the Kentucky lawmaker’s yard has been charged with assaulting a member of Congress as part of a federal plea agreement. And his lawyer echoed what’s long been suggested by neighbors: The attack stemmed from a dispute about yard maintenance.

Rene Boucher has signed the plea agreement but no date has been set for his guilty plea for the attack on the Republican senator, according to Josh J. Minkler, U.S. attorney for the Southern District of Indiana.

“Assaulting a member of Congress is an offense we take very seriously,” Minkler said in a release. “Those who choose to commit such an act will be held accountable.”

Boucher faces possible prison time. His attorney says Boucher is “very regretful” about the attack and that it had to do with the upkeep of their yards. Paul and Boucher are longtime neighbors in Bowling Green.

“This is over a matter that most people would regard as trivial,” Boucher’s attorney, Matt Baker, said in a phone interview Friday. “It has to do with yards and the maintenance of those.”

Boucher is “very meticulous” about how he maintains his yard, while Paul takes “a much different approach” to the upkeep of his property, Baker said.

“It all goes to large piles of leaves and branches and yard clutter that were placed on the property line,” Baker said.

Some residents of the gated neighborhood had speculated the attack was motivated by a dispute over yard debris. But Paul’s office has rejected that. Paul told the Fox News Channel in November that ultimately, the motive does not matter.

Boucher, a retired anesthesiologist in his late 50s, already faces a misdemeanor assault charge in state court in Kentucky. He has pleaded not guilty to that charge.

Baker said Friday that he’s hopeful the state charge will be dismissed now that Boucher has reached the plea agreement on the federal charge.

Paul, a former presidential candidate, was attacked Nov. 3 while mowing his lawn at his home. A close friend of Paul’s said the senator had gotten off his riding lawn mower to remove a limb when he was tackled from behind. Paul has said he never saw the attacker because he was facing downhill and wearing ear protection from the noise of his lawn mower.

Paul suffered six broken ribs in the attack.

He returned to Washington less than two weeks later but developed pneumonia when he returned to Kentucky. Paul has since said he’s recovering well from the attack.

Baker said Friday the attack was “completely, 100 percent out of character” for Boucher. He said his client is looking forward to getting the case resolved.

Boucher faces up to 10 years in prison and a $250,000 fine in the federal case.

“He is facing the possibility of incarceration, but I’m hopeful that it won’t be anything toward the top end,” Baker said.

Minkler’s office was assigned the case after a U.S. attorney in Kentucky recused himself. The case was investigated by the FBI’s Louisville office.