The leader of a drug trafficking ring charged in what’s been described as Hawaii’s largest crystal meth case is avoiding a mandatory 20-year minimum sentence because he testified at trials against his co-defendants.

U.S. District Judge Leslie Kobayashi noted at John Tai’s sentencing Wednesday that he was assaulted in prison and his sister-in-law was shot because of his cooperation. Taking his “substantial cooperation” into account, Kobayashi sentenced him to about eight years in prison. He’s already served about five years.

Defense attorney Alan Baum says Tai and his family continue to fear retaliation.

The case involved 19 defendants, many of them Tai’s family members. They trafficked millions of dollars’ worth of meth to Hawaii.

Prosecutors credit Tai’s cooperation in obtaining convictions against the ring’s supplier and others.