A Zumbro Falls, Minn., diamond merchant was sentenced Friday to just over 16 years in federal prison for conspiring to distribute more than a ton of marijuana, laundering money and transporting stolen gemstones.

Richard Allen Kay, 39, who did business as Kay Diamonds, opted not to plea-bargain and took the unusual step of pleading guilty to 13 counts in the indictment. U.S. District Judge Ann Montgomery ordered him taken into custody immediately and ordered him to pay a $500,000 fine, plus $300,000 in restitution to Ohio-based Sterling Jewelers Inc.

Kay admitted to participating in a conspiracy to distribute high-grade marijuana from 1995 through March 2011. The pot sold for as much as $5,000 a pound, he said. He also admitted to transporting stolen gemstones in a conspiracy involving an unidentified insider at Sterling. Kay's company was not affiliated with Sterling, the parent company of the national Kay Jewelers chain.

Altogether, five people have pleaded guilty in the case.

• Jamie Allen Davidson, 40, of Rochester, was sentenced Friday to five years in prison after pleading guilty in January to one count of conspiracy.

• Shawn Robert Milliken, 32, of Rochester, was sentenced Thursday to four years and two months after pleading guilty in October to one count of conspiracy.

• Jason Ray Meek, 37, of Rochester, pleaded guilty to one count of conspiracy in October and is scheduled to be sentenced Aug. 15.

• Brandon Christopher Lusk, 38, of Rochester, pleaded guilty in October to one count of conspiracy and one count of money laundering and is scheduled to be sentenced Aug. 13.

Dan Browning • 612-673-4493