ST. PAUL  — A central Minnesota man accused of trying to hire someone to kill the fiance of a former mistress has been sentenced to five years in prison.

Robert James Schueller, 30, was sentenced Friday in United States District Court for sending threatening communication. Schueller pleaded guilty in May, after being charged in January with the use of interstate commerce facilities to commission the killing, according to a press release.

“This is about as serious a crime as I have seen in a long time,” U.S. District Judge Richard H. Kyle told Schueller 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.