Election experts are raising serious red flags after learning that Texas Attorney General Ken Paxton voted in six elections while registered at an address where he does not live, ProPublica reported Tuesday.

The Texas attorney general has been registered to vote at his Collin County home—where he has not lived since his divorce two years ago, according to filings by his ex-wife, State Senator Angela Paxton.

It’s not entirely clear where Mr. Paxton has resided since, but prior reporting linked him to another home in Denton County—making him ineligible to participate in elections in Collin County. Doing so is a second-degree felony punishable by a fine up to $10,000 and up to 20 years in prison. Election lawyers have cautioned that this kind of voter fraud is incredibly hard to prove.

Voter rolls showed that Paxton voted in Collin County in the March Republican primary, and again in May when he became his party’s nominee for the U.S. Senate.