Expletive-filled Twitter postings about drug use, insults to the military, suggesting "death to the world police" and the public rape of U.S. Senators ended a congressional campaign staffer's job on Monday.

Republican candidate David Gerson said former staffer Boone Leach's Twitter messages, posted over a series of months, were "undeniably unacceptable."

Gerson and campaign chair Marianne Stebbins said no one with the campaign was aware of them before they were brought to their attention by a Star Tribune reporter on Monday. Leach, whom Gerson said was 20 years old, was terminated from his campaign job shortly thereafter.

"We can't have him involved in the campaign," Gerson said.

Stebbins, chair of David Gerson's campaign, said that Leach was hired in November and was gone as of Monday. He had done voter contact work for about $200 a week and seemed like a "sweet kid," she said.

Gerson is challenging U.S. Rep. John Kline for the Republican nod in Minnesota's Second Congressional District.

The Twitter account under which Leach posted appeared to have been deleted on Monday afternoon.

Before the account was deleted, the Star Tribune captured some of tweets. (The tweets contain language and statements readers may find offensive.)

Many are unprintable but among them are a tweet from three months ago in which he wrote: "There is no moral difference between the affordable care act and the nazi holocaust. Every senator who voted for it should be raped publicly." Two months ago, he posted: "Working in politics at all is seriously, seriously selling your soul to evil. That's where I am right now."

He also posted an insult to the Marines, adding that "Soldiery is not a noble profesion (sic)" six months ago. Kline is a marine veteran.

Gerson said that he spoke to Leach on Monday about the postings.

"He feels terrible about it," Gerson said. "He realizes it was inappropriate."

The Star Tribune was unable to obtain working contact information for Leach.