First it was an email warning Steve House, the Colorado GOP chairman, to hide his family members and “pray you make it to Cleveland.” Then there was the angry man who called his cell phone and told him to put a gun down his throat.

“He said, ‘I’ll call back in two minutes and if you’re still there, I’ll come over and help you’,” House recalled.

Since Donald Trump came up empty in his quest for delegates at the Republican state assembly in Colorado Springs nearly two weeks ago, his angry supporters have responded to Trump’s own claims of a “rigged” nomination process by lashing out at Republican National Committee delegates that they believe won’t support Trump at the party’s convention — including House.

The mild-mannered chairman estimates he’s gotten between 4,000 and 5,000 calls on his cell phone. Many, he says, have ended with productive conversations. He’s referred the more threatening, violent calls to police. His cell phone is still buzzing this week, as he attends the RNC quarterly meetings in Florida, and he’s not the only one.

In hotel hallways and across dinner tables, many party leaders attending this week’s meetings shared similar stories. One party chair says a Trump supporter recently got in his face and promised “bloodshed” if he didn’t win the GOP nomination. An Indiana delegate who criticized Trump received a note warning against “traditional burial” that ended with, “We are watching you.”

The threats come months ahead of a possible contested convention, where Trump is all-but certain to enter with a plurality of delegates bound to him on the first ballot, but he could lose support on subsequent ballots as rules will allow delegates to vote however they choose. And although the harassers are typically anonymous, many party leaders on the receiving end of these threats hold Trump himself at least partly responsible, viewing the intimidation efforts as a natural and obvious outgrowth of the candidate’s incendiary rhetoric.

The Trump campaign did not respond to a request for comment.