A man from southern Oklahoma is being held on a $1 million bond, accused of threatening to attack Senator Jim Inhofe with a sledgehammer.

Court documents show 23-year-old Walker Wilson was being monitored by state officials. In a string of tweets, investigators said Wilson posted “somebody tell Jim Inhofe to watch his back.” Pictures of Wilson holding a sledgehammer were attached to the post.

Investigators said Wilson was frustrated about not getting a tax refund, stimulus check or unemployment.

Investigators said Wilson also made threats against law enforcement.