Published: Feb 11, 2011 10:25 PM EST
Updated: Feb 11, 2011 7:32 PM EST

AUSTIN, Texas- A 13-year-old boy accused of helping his 12-year-old girlfriend to kill her relatives in suburban Dallas has reached a plea agreement with prosecutors that will keep him from going to trial on capital murder charges.

Details of the agreement reached this week have not been released, but police say the teen will serve at least 10 years behind bars. He had been facing a maximum 40-year sentence and was set to go to trial Monday.

The boy and his girlfriend were charged in the Aug. 17 shootings that killed 46-year-old Darlene Nevil at her home in Garland, Texas. Her husband, Alan Nevil, 48, was also shot, but did not die until Sept. 2. He was able to tell police who shot him.

(Copyright 2011 by The Associated Press. All Rights Reserved.)