JEFFERSON CITY, Mo. -- A 61-year-old Missouri man serving a life sentence without parole for three marijuana felonies is asking Gov. Jay Nixon to grant him clemency.

Jeff Mizanskey has spent the last 20 years in prison after he was convicted and sentenced as a "prior and persistent drug offender" under Missouri law. That law allows sentences of life without parole for people with three felony drug convictions. Police say the Sedalia man conspired to sell six pounds of pot to a dealer connected to Mexican drug cartels.

On Monday, supporters of Mizanskey's clemency effort delivered a petition with nearly 370,000 signatures to the governor's office.

A spokesman for Nixon said the governor's office has received an official request for clemency and is currently reviewing the case.