A Pentagon cybersecurity contractor has been charged with making a death threat to a member of Congress for supporting legislation that would require public schools to vaccinate students, according to a recently unsealed criminal complaint.

Darryl Albert Varnum was charged with making a threat against an official for his June 26 voicemail to the Florida office of a member of Congress, saying he would “personally fucking kill” the lawmaker for backing the Vaccinate All Children Act, according to the complaint, filed in U.S. District Court in Maryland on July 5.

The complaint, unsealed on July 8, identifies the target only as “Congressperson #1,” who it says is a “public supporter” of the vaccine bill. The Daily Beast reported the threat was made to Rep. Frederica Wilson (D-Fla.), who introduced the vaccine legislation in May.

“I’m gonna kill your ass if you do that bill,” Varmum said on the voicemail, according to the complaint. “I swear. I will fucking come down and kill your fucking ass. And you’re a Congressperson, that’s fine. I hope the fucking FBI, CIA, and everybody else hears this shit. If you’re taking away my rights. This is the United States of America, bitch. Get the fuck out. I will come down there and personally fucking kill you. I am dead fucking serious. I wanna see you motherfuckers at my door, if you’re legit. The HR bill you just pushed through, ah fuck you. I’ll tell you what I’ll come down to Miami bitch. I’ll fuck you up. Luke Cubans don’t even know.”

Investigators traced the phone number back to Varnum, who was employed as a contractor at the Defense Information Systems Agency headquarters, which “requires him to have access to sensitive information,” according to the complaint.

Just 12 minutes after leaving the voicemail, Varnum complained about the bill in a Facebook post, according to the complaint.

“I’m done with this bullshit. Time to step up or ship out,” he wrote. He later added: “All of our guns are next. Been trying for years!”

In 2015, Varnum’s wife called police to report her husband was having “behavioral issues,” including yelling that ISIS fighters were out to get him. A .45 caliber Ruger pistol is registered to him, the complaint says.

It’s unclear whether Varnum is in custody. Capitol Police, who led the investigation, declined to comment. A federal magistrate judge approved warrants for Varnum’s arrest and for a search of his phone and other electronic equipment.

A lawyer representing Varnum did not immediately return HuffPost’s request for comment.