PARIS, Texas - A Lamar County teen charged with killing his grandmother in December 2014 has rejected a plea deal.

Christian Sims, 18, is charged with first-degree murder in the death of his grandmother 66-year-old Annie Sims.  He and his girlfriend were arrested at a Sapulpa motel.

KXII, the CBS affiliate in Sherman, Texas reports Sims' 18-year-old girlfriend, Ashley Morrison is also charged with murder. Annie Sims was found shot to death in her home in December 2014.

Using credit card activity, Lamar County authorities tracked Sims and Morrison to a Sapulpa motel on December 18, 2014, where Sapulpa Police arrested them. 

A pre-trial hearing for Sims and Morrison is set for May 4 with Sims' trial scheduled to begin June 6.  If convicted, he faces life in prison.