The St. Paul Bomb Squad neutralized the IED.
Superior Mayor Jim Paine made the announcement Tuesday morning.
A bomb disposal team destroyed the explosives found in Crow Wing County.
The 65-year-old and his girlfriend said they planned to sue the county.
Eric Reinbold, of Oklee, was sentenced in federal court on Friday.
It happened just across the Minnesota border.
He allegedly told people he intended to target a judge and a prosecutor.
The three men from Illinois have been indicted with more charges.