A Minnesota man serving a life sentence without parole after being convicted of two murders is now vying for a U.S. Senate seat.

Leonard Richards, 75, has found a loophole that has allowed him to legally run for federal office, despite his criminal record.

Minnesota law bars felons from running for state-level offices but does not prevent them from seeking federal positions.

Richards was found guilty of killing his half-sister, May Wilson, in 1982 and of fatally shooting his lawyer, Robert Stratton, five years later.

He is now seeking the nomination of Minnesota's Democratic-Farmer-Labor (DFL) Party, which will hold its primary Aug. 14. Richards is looking to upset U.S. Sen. Amy Klobuchar, who has held the seat since 2007.

His candidacy, while legal, has angered Stratton's sister, who told the Star Tribune of Minneapolis that she hopes voters take the time to learn about Richards' crimes before they cast a vote.

"I know he won’t win against Amy Klobuchar, but even one vote for this murderer is too many,” she told the newspaper.

"I know he won’t win against Amy Klobuchar, but even one vote for this murderer is too many.” — Sister of murder victim

She added that she hopes the state's laws can be changed to prevent felons from seeking federal office.

But Bert Black, a legal adviser for the Minnesota Secretary of State’s Office, said in an email to the Associated Press that courts have ruled that felons – even those currently incarcerated – cannot be prohibited from filing an affidavit of candidacy.

Richards has taken advantage of the loophole in the past.

In 1992 he ran in the Democratic primary for a congressional seat and earned more than 14,500 votes. He ran again in 1994, winning 4,000 votes.

Because Richards is behind bars without parole, there's no chance that he would be able to serve if elected, the Star Tribune reported.

The Associated Press contributed to this report.