David Lane, a member of The Order, was 68.
A spokeswoman for the U.S. Department of Justice Federal Bureau of Prisons confirmed Lane's death, which happened shortly after 9 a.m. The exact cause of death is not yet known and is pending the results of an autopsy.
Lane was serving a 190-year consecutive life sentence for racketeering, conspiracy and violating the civil rights of Berg, who was shot and killed on June 18, 1984, in the driveway of his home in Denver.
Berg, a former attorney, was a controversial radio talk show host who was also Jewish, and received death threats from The Order months before his death at age 50.
No one was ever convicted of Berg's murder, yet several members of The Order were convicted of conspiracy, racketeering and the violation of his rights resulting in his death.
Another member of The Order, Bruce Pierce, 53, is currently serving what amounts to a life sentence in a federal prison in Allenwood, Pennsylvania.
Lane, also a member of the Ku Klux Klan and the Aryan Nation, was also an author who is said to have coined the "14 Words," a white supremacist slogan.
According to an autobiographical essay, Lane was born in Iowa to a household of four children and an abusive, alcoholic father who left the family when Lane was four. Lane's mother was unable to support her children, who were taken to an orphanage.
Lane was eventually adopted out to a minister and his wife. He graduated from high school in Aurora, and soon began membership in a series of white supremacist groups in Colorado and other states.
(Copyright KUSA*TV, All Rights Reserved)