There was a break-in over the weekend at the Las Vegas office of U.S. Sen. Dean Heller, R-Nevada, a Republican senator who could be a critical swing vote on the GOP health care bill.

The Las Vegas Metropolitan Department confirmed a break-in occurred Saturday morning at Heller’s office in southwest Las Vegas but did not give details, citing an ongoing investigation, the Las Vegas Review-Journal reported.

A “threatening note” also was left at the office after the break-in, according to 8 News Now, based on an anonymous source. Las Vegas police would not confirm any information about a note to local media outlets.

Representatives for Heller did not immediately respond to a message left at his Las Vegas office or to questions sent by email Monday morning. The voice mail box for Heller’s Washington office was full.

Heller has been under tremendous pressure from both the left and the right on his vote on the health care bill. Republican lawmakers have been steadfast for years in their promise to “repeal and replace” the Affordable Care Act, President Barack Obama’s signature measure — a pledge President Donald Trump frequently invoked on the campaign trail.

But as The Post’s David Weigel pointed out, Heller is the only Senate Republican facing re-election in 2018 in a state won by Democratic candidate Hillary Clinton last year. His unique position has made him the focus of several advertising campaigns trying to lobby for his vote.

Last month, Heller came out against an earlier iteration of the GOP’s health care bill, becoming the fifth Republican senator to do so at the time. At a June 23 news conference, Heller said he was particularly concerned about potential cuts to Medicaid, as well as the impending loss of insurance for those struggling with mental-health and substance-abuse issues.

“I’m telling you right now, I cannot support a piece of legislation that takes away insurance from tens of millions of Americans and hundreds of thousands of Nevadans,” Heller said then.

Three weeks later, Heller is in no less a precarious spot when it comes to voting on the GOP’s new proposal to remake the Affordable Care Act, unveiled by Senate Majority Leader Mitch McConnell, R-Kentucky, last week.

Currently two Republican senators — Susan Collins of Maine, and Rand Paul of Kentucky — have publicly said they continue to oppose the GOP’s health care bill. Just one more “no” vote from a Republican senator would mean the bill would not have the 50 votes it needs to pass.

When U.S. Sen. John McCain, R-Arizona, announced he needed to recover from surgery and would be absent from a vote Saturday night, McConnell said the Senate would postpone the vote.