OMAHA, Neb. (AP) — The leader of a large synthetic drug-dealing business has been sentenced to 15 years in federal prison.

U.S. District Judge Joseph Bataillon sentenced 48-year-old

John Ways Jr. on Friday. Ways is the former operator of the head shop Exotica. He was found guilty last year of running a multimillion-dollar money laundering scheme involving the sale of synthetic controlled substances. Prosecutors say the stores sold drug paraphernalia and controlled substances that included synthetic drugs such as K2 and bath salts.

The U.S. Attorney’s Office says the Exotica operation is the most extensive enterprise involving the sales of synthetic controlled substances to be prosecuted federally in Nebraska.