CENTENNIAL, Colo. -- A man described by a shooting victim's family as a beast and monster was sentenced to life in prison Tuesday, without the possibility of parole.

Sir Mario Owens, 22, received the life sentence after being convicted of first-degree murder in the July 4, 2004 slaying of Gregory Vann at Lowry Park in Aurora.

"Anyone who can disregard human life without a second thought, gloat about it and be proud of it, is a cancer to society," said Wauneta Vann, the victim's cousin.

Owens was sentenced to an additional 64 years in prison for trying to kill Javad Marshall Fields and Alvin Bell during the same Lowry Park incident. Both men survived that shooting.

Marshall Fields was scheduled to testify against Owens, but he and his fiancee, Vivian Wolfe, were gunned down in June 2005 just days before he was to take the stand.

Owens and his friend Robert Ray have been charged with murder in connection with those shootings. Prosecutors are seeking the death penalty against both in the 2005 case.

Marshall Field's mom, Rhonda Fields, sat in on Tuesday's sentencing hearing. "Life without parole with 64 years. That is a very long long time," Fields said. "So he has a lot of time on his hands to think and reflect on what he did."

Chief Deputy District Attorney John Hower said, "I think it's totally appropriate," referring to the life sentence. "We're very satisfied under the circumstances."

Hower said Owens needs a lifetime to "think about the devastation he has wreaked on these families and on the community."

Ray, was sentenced in February to 108 years in prison for being an accessory to murder in Vann's death.

No trial dates have been set for Owens or Ray in the 2005 slayings.