The District Attorney’s Office’s star witness in the prosecution of co-defendants Rhonda Wisto and Frank York has followed through with his plea deal and pleaded guilty—a move which could have him out of prison in 15 years.

Jason Greenwell, 22, of Nipomo, formally pleaded guilty in San Luis Obispo County Superior Court on May 21 to one count of second degree murder for his role in the 2010 murder of 15-year-old Santa Maria teen Dystiny Myers.

Greenwell was only defendant out of five who admitted his role to investigators and agreed to plead guilty to the reduced charge in exchange for his testimony against Wisto, York, Ty Hill, and Cody Miller.

On March 14, Greenwell took the stand, avoiding eye contact with his former friends, and recounted how Myers was attempting to leave the residence at which they were all congregated. Moments later, he testified, Hill told the group to put on dark clothes and gloves, and they followed Myers into York’s room, where Greenwell stated that he saw Myers bound at the wrists with tape. He testified that he helped hold her down while the group viciously beat her.

Wisto and York’s defense attorneys attempted to poke holes in Greenwell’s testimony, noting that there were a number of inconsistencies early on in the narrative that later changed, and attempted to paint him as a snitch who was trying to save his own skin.

Under the deal, Greenwell must serve a minimum of 15 years behind bars before he’ll be eligible for parole. He’s due for sentencing May 28.