An 80-year-old man who admitted running a sprawling multistate marijuana-dealing operation faces sentencing in federal court in Massachusetts.

Marshall Dion faces up to seven years in prison under a plea agreement with prosecutors who say he has been selling marijuana for decades.

In 1985, Dion crashed a single-engine plane in Kenosha County, Wisconsin, and then crawled along a field with two broken ankles as cash floated in the air. He denied that the $112,000 recovered from the crash scene was his.

A stop for speeding in 2013 in Junction City, Kansas, led authorities to Massachusetts and Arizona, where they found about $15 million in cash, nearly 400 pounds of marijuana and ledgers detailing drug deals going back to 1992.

Sentencing is scheduled for Thursday afternoon in Boston.