Sen. Rand Paul (R-Ky.) is recovering after being assaulted at his Kentucky home Friday, joining a growing list of lawmakers who have been injured or threatened with violence this year.

Paul, a second-term senator, suffered a minor injury when he was assaulted at his Warren County, Ky., home Friday afternoon. Kelsey Cooper, Paul's ­Kentucky-based communications director, said in a statement Saturday that the senator "was blindsided and the victim of an assault. The assailant was arrested, and it is now a matter for the police."

It was unclear whether politics was a motivation for the attack, according to a senior aide to the senator, who spoke on the condition of anonymity because the aide was not authorized to speak about the incident.

Kentucky State Police charged 59-year-old Rene Boucher with fourth-degree assault with a minor injury. He is being held at Warren County jail on $5,000 bond, state police said.

Boucher is an anesthesiologist and the inventor of the Therm-a-Vest, a cloth vest partially filled with rice and secured with Velcro straps that is designed to help with back pain, according to the Bowling Green Daily News.

Troopers responded to Paul's residence at 3:21 p.m. Friday after reports of an assault. Upon arrival, troops determined that Boucher "had intentionally assaulted Paul, causing a minor injury," state police said.

On Sunday morning, Paul made his first public comments on the incident via Twitter, saying that he and his wife, Kelley, "appreciate the overwhelming support after Friday's unfortunate event. Thank you for your thoughts and prayers.

Robert Porter, who has known the senator and his family for more than 20 years, said he went to see his friend Saturday evening. He would not specify where or how the senator was injured but said Paul "didn't get any severe injuries to his face."

"He's in some pain, but he's going to be fine," Porter said, adding that Paul's return to Washington will be a "game-time decision" but that Paul is planning to return to work at some point in the coming days.

Paul and Boucher live in the same gated community along Rivergreen Lane in Bowling Green, Ky., according to Porter and another person close to Paul who spoke on the condition of anonymity out of respect for the senator.

Porter said Paul was mowing his lawn and wearing ear plugs Friday afternoon just before the alleged assault. Shortly after stepping off the riding mower to do something in the yard, Paul "got blindsided. He didn't hear him or see his neighbor come over," Porter said.

"He hadn't really talked to his neighbor in years," Porter said. Although the properties are adjacent, there is a large amount of land between the houses, so the lack of interaction would not be surprising to locals, he added.

Porter said he was unaware of any previous incidents between Paul and his neighbor.

Porter said that he and Paul and their spouses raised their kids together. He also traveled with the senator to Guatemala in 2014 as part of a missionary trip to provide free eye care to hundreds of impoverished patients.

Paul, 54, has served in the Senate since 2011. He is an ophthalmologist who has practiced in Bowling Green, Ky., where he moved with his wife in 1993.

He ran unsuccessfully for president in 2016, focusing the closing months of his bid on attacking then-candidate Donald Trump and his readiness for office.

In recent months, he was a lead opponent of Republican attempts to repeal the Affordable Care Act.

But more recently, Paul has emerged as a leading defender of Trump's policies and has golfed with the president at Trump's Virginia golf course.

Porter said he didn't know whether Paul and Boucher had ever worked together at local medical facilities.

A Facebook page purportedly used by Boucher says he is a former U.S. Army pain management specialist and graduated from the College of Osteopathic Medicine in Des Moines in 1984. The page also includes links to articles or memes critical of Trump and a news article about a Montana Republican congressional candidate who attacked a reporter the day before winning his seat.

The page was overrun late Saturday by other Facebook users criticizing Boucher for his alleged assault on Paul.

While it is unclear whether the attack was politically motivated, an unprecedented wave of threats against House and Senate lawmakers this year has prompted congressional security officials to review and follow up on thousands of threatening messages to members of both parties.

The threats turned to violence this summer when House Majority Whip Steve Scalise (R-La.) was shot and nearly killed by a gunman who showed up at a congressional baseball practice in Alexandria, Va.

More recently, Rep. Frederica S. Wilson (D-Fla.) skipped several days of votes after threats were made against her after she sparred with Trump over the treatment of the widow of a soldier killed in Niger.

In addition to Scalise, Paul and Wilson, Rep. Al Green (D-Tex.) has faced threats since suggesting that Trump should face impeachment. And several GOP lawmakers, including Sens. Jeff Flake (Ariz.) and Marco Rubio (Fla.), have faced threats. Rubio, another failed 2016 presidential candidate, was spotted in July walking around the U.S. Capitol with three U.S. Capitol Police officers wearing suits and ties.

Brian Fung and David Weigel contributed to this report.

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