The abuse allegedly happened in 2017.
Nathan Paul Grondahl learned his fate in a federal court this week.
Jory Wiebrand pleaded guilty to his charges in January.
He was caught having sex chats and sending a nude pic, authorities say.
Phillip Arlan Koontz, 53, pleaded guilty earlier this year.
Police say it happened during a late 2019 basketball game.
Five of the suspects are Minnesotans.
Authorities are now investigating.
The victim was 11 years old at the time.
One of the suspects says it was a prank gone wrong.
The crimes occurred in Windom, Cottonwood County.
The two met online and used apps like Amino to communicate.
The operation was carried out by the Crow Wing County Sheriff's Office.
Steven Dale Row's obituary says he died May 23 near Grove City.
Police say that online solicitation "continues to be a statewide problem."