Rene Boucher, Sen. Rand Paul’s neighbor, was charged with assaulting a member of Congress for tackling Paul to the ground after witnessing him stack brush onto a pile in November.

The charge is a felony under federal law, and Boucher, 58, faces up to 10 years in prison and a $250,000 fine, the U.S. Attorney’s Office for the Southern District of Indiana announced Friday.

“Assaulting a member of Congress is an offense we take very seriously,” Josh Minkler, the U.S. attorney, said.

Boucher allegedly tackled Paul, R-Ky., while he was mowing his lawn, wearing headphones. Boucher, a retired anesthesiologist, allegedly saw Paul stack brush onto a pile near his own property, and “had enough.”

The incident left Paul with six broken ribs and fluid buildup around his lungs.

Boucher signed a plea agreement, though he hasn’t yet entered his guilty plea.

He denied his tackling of Paul was politically motivated, and Boucher’s lawyer said the two had an ongoing dispute over leaf and grass clippings.

But Paul’s neighbors dismissed suggestions that the attack stemmed from their landscaping feud.