A Lawrence man who helped create a global market for synthetic marijuana known as K2 and other designer drugs was sentenced Monday to seven years and three months in federal prison.

Bradley Miller, 57, pleaded guilty to one count of conspiracy, one count of misbranding and one count of mail fraud, according to a news release from U.S. Attorney Barry Grissom.

In the plea agreement, Miller admitted he had conspired with his brother Clark Sloan and Sloan’s son Jonathan Sloan to manufacture and sell the drugs, the release said.

Bradley Miller

Miller and the Sloans’ designer drug business had its beginnings in a retail shop Persephone’s Journey at 1103 Massachusetts St., the release said.

Miller and Jonathan Sloan also owned Bouncing Bear Botanicals at 14501 S. U.S. 59 Highway in Oskaloosa.

The business grew until it encompassed a chain of suppliers, retailers, wholesalers and business associates in Kansas and across the U.S. The men also did business in Canada, South America, Europe and Asia.

They made at least $3.3 million from the sale of the drugs.

Miller created the recipes for K2 and manufactured them, the release said. There were four products with varying levels of potency.

A federal jury convicted Clark Sloan, of Tonganoxie, and Jonathan Sloan, of Lawrence, last September on 20 counts of conspiracy, misbranding, mail fraud, smuggling and money laundering. Sloan received seven years and three months in prison, and his son received eight years.