A federal court convicted a Minnesota head shop owner on several counts in a case brought against him for selling synthetic drugs such as Spice and K2.

Jim Carlson sold synthetics from his shop Last Place on Earth in downtown Duluth, MN. Officials tried to prevent him from selling the substances multiple times, creating an ordinance requiring a license to sell synthetics, and requiring Carlson to pay for two police officers stationed outside the shop. Authorities finally shut the business down in July after conducting multiple raids and seizing cash, guns and drugs.

Charges were brought against Carlson under several federal laws, including one against "analogue" drugs, defined as substances with similar chemical structures and effects to scheduled substances. He was also charged with dealing in misbranded drugs and conspiracy. Carlson was found guilty of 51 of the 55 counts against him. His girlfriend Lava Haugen and his son Joseph Gellerman were also found guilty on several counts.

Synthetic drugs occupy a legal grey area; manufacturers of the drugs constantly update the formula to stay one step ahead of the law. Carlson didn’t deny selling the substances, and his defense argues that he did nothing illegal. Carlson’s attorney, Randall Tigue, said they will ask for a new trial, explaining that he was prohibited by the judge from introducing statements from government officials that say combating the sale of synthetic drugs is difficult because they’re often legal.

Acting US Attorney John Marti said prosecutors cannot comment on the verdicts because of the ongoing federal government shutdown. Prosecutors haven’t indicated what they’ll seek for sentences, but the possible maximum sentences for the charges range from three to 20 years.