A Hermantown man was sentenced Wednesday to 60 years in prison for sexually assaulting a pre-teen girl.

Brian Arthur Barthman, 47, was sentenced by Judge Shaun Floerke on Wednesday to two 30-year prison sentences to be served one after the other, according to the St. Louis County Attorney's Office. Barthman was found guilty in March of three counts of first-degree criminal sexual conduct and three counts of second-degree criminal sexual conduct.

St. Louis County Attorney Mark Rubin said the sentence is believed to be the longest-duration sentence for a sex crime in the county since Minnesota's sentencing guidelines were implemented in the early 1980s.

Assistant St. Louis County Attorney Rebekka Stumme, who prosecuted the case, said in a statement, "Words fail to do justice under the unimaginable circumstances, but this sentence is a good start."

Authorities were contacted by mandatory reporters in the Hermantown school district in 2015 after the girl said that Barthman, who was known to her, had touched her on multiple occasions. She also told authorities that in addition to the touching, he asked her to have "some X" and when she said no, he forced her to have intercourse, according to the complaint. She said she declined to view " 'naughty pictures' and video" with Barthman, according to the criminal complaint. She said she was unsure how old she was when it began.

Barthman also is facing a federal charge for possessing child pornography involving children younger than 12 years old. The indictment, filed in October, alleges that Barthman possessed hundreds of child pornography images that included children subjected to sexual abuse and other violence. Barthman has pleaded not guilty to the federal charge and his trial is scheduled for June 26 in Duluth.