Olson email allegedly threatened to shoot her in the head.

Prosecutors have charged a North Dakota man with making threats against the state's Democratic senator, Heidi Heitkamp.

Fifty-five-year-old Kevin Lee Olson, of Fargo, made his initial appearance in court Tuesday on a charge of having made a threatening communication. He told the judge he doesn't want an attorney and a detention hearing was scheduled for Thursday.

Authorities allege that Olson sent an email to the senator's office last month threatening to shoot her in the head. Although court documents didn't specify which senator had been threatened, Heitkamp's office confirmed it was she.

Heitkamp told KFGO-AM (http://bit.ly/2iaH03U ) that her office notified the authorities, who decided it was serious enough to warrant intervention.