Duluth head shop owner James Carlson and his girlfriend Lava Haugen are going to lose more than freedom after being convicted for their roles in selling highly addictive synthetic drugs.

Under a final forfeiture proposal filed Wednesday in U.S. District Court, federal authorities would seize $6,532,125 in money and property from the couple, who sold the drugs at the Last Place on Earth in Duluth for more than three years.

A jury found Carlson and Haugen guilty in October, and last week Judge David Doty sentenced Carlson to 17 years and Haugen to five years in prison.

Federal authorities had combed their bank accounts and searched their homes, contending the funds and property should be forfeited because they were acquired as a result of a criminal enterprise.

Among the funds and items identified were $1.3 million in a Wells Fargo Bank account, $1.2 million from the Superior Savings Bank and such vehicles as a 2012 Ford F-150 pickup, a 2012 Jeep Grand Cherokee and two Polaris snowmobiles.

Federal authorities also plan to seize the Last Place building at 120 E. Superior St., where long lines of customers often gathered to buy the synthetic drugs.

Investigators found $83,322 in cash on the premises, which is part of the amount facing forfeiture.

The government also is seizing a property in Palisade, Minn., a condo in Winchester, Nev., and a house in Cozumel, Mexico.

A man who lives at the Nevada condo claims an interest in it and has challenged that seizure, so prosecutors said in their motion they are not seeking final forfeiture at this time, anticipating more investigation before the matter is resolved. Authorities also are seizing a five-acre lot that Carlson owned in Cozumel.

Investigators located and seized $156,404 from a safe and $27,320 found at a residence in Superior, Wis.

The details were disclosed in a motion filed by U.S. Attorney Andy Luger and Assistant U.S. Attorney Surya Saxena, who prosecuted the couple.