The FBI is investigating a suspicious package delivered to Senator Rand Paul’s Bowling Green, Kentucky home, reports CBS Louisville affiliate WLKY. A large envelope containing what appeared to be a white powder arrived Monday.

Authorities are attempting to determine whether the envelope’s contents are hazardous.

Paul, a Republican, tweeted about the package Monday night, saying he had been “a repeated target of violence.”

“I take these threats immensely seriously,” Paul wrote.

Paul and his family were threatened in 2018 while he was at a stop in Leitchfield, Kentucky. Paul said a man threatened to kill him and “chop up” his family with an ax. The year before, Paul suffered multiple broken ribs and damaged a lung when he was tackled by Rene Boucher.

The 2017 attack was described as having escalated from a dispute between neighbors.  

Paul subsequently suffered from pneumonia and underwent multiple medical procedures, including a hernia surgery related to the assault.

Boucher pleaded guilty to assaulting a member of Congress and served a 30-day sentence at a federal prison in Illinois. Paul was awarded more than $580,000 in damages and medical expenses by a jury in 2019 after filing a lawsuit against Boucher.