DULUTH — The city of Duluth is asking a judge to shut down a downtown head shop that sells synthetic marijuana.

The city argues the Last Place on Earth has created a public nuisance. Business owners have long complained about the throngs of customers who gather outside the shop.

Both supporters and critics of the business and its owner, Jim Carlson, crowded the St. Louis County Courthouse for Friday’s hearing.

Carlson’s attorney Randall Tigue argued the state’s nuisance law is unconstitutionally vague.

Judge Shaun Floerke appeared skeptical of the city’s request. He asked how a judge could prevent the sale of synthetic drugs, when it’s something the state and federal governments haven’t been able to do.