A Stearns County man who devised a murder-for-hire plot to kill his ex-girlfriend’s fiancé was sentenced Friday in U.S. District Court.

Robert James Schueller, 30, was sentenced to five years in prison. He pleaded guilty in May, after being charged in January with the use of interstate commerce facilities in the commission of murder-for-hire — a federal crime.

“This is about as serious a crime as I have seen in a long time,” said U.S. District Judge Richard H. Kyle as he addressed Schueller directly on Friday.

According to an affidavit filed this winter, Schueller had an affair in 2013 with a woman while he was married to another woman. The three worked at Nomad Pipeline Services, Schueller’s family-owned business. The woman ended the affair in August 2013 and began a relationship with another man.

After fruitlessly attempting to reignite his relationship with the woman, Schueller contacted a co-worker and asked him for help hiring a hit man to kill his former lover’s new boyfriend.

Schueller and the co-worker corresponded for months, according to the affidavit. In March 2014, Schueller sent one of his employees from Minnesota to Wisconsin to deliver $10,000 in cash to the co-worker to pay the hit man. In May, the co-worker — who later told law enforcement that he’d never wanted to orchestrate the murder — told Schueller he wouldn’t be able to find a hit man and returned the $10,000.

Later, Schueller admitted to contacting several other co-workers for help in harming his former girlfriend’s new boyfriend, according to a May release from the U.S. attorney’s office. At one point, Schueller paid his sister-in-law $500 to try to seduce the new boyfriend and break up the ­relationship.