SIDNEY, Neb. (AP) — The Nebraska Supreme Court has upheld the first-degree murder conviction of a man for killing a 30-year-old Sidney woman.

Larry Martinez was sentenced to life in prison for the murder charge, as well as 10 to 50 years in prison for a gun count in the July 2012 shooting death of Mandy Kershman, whom he had been dating. Prosecutors say Martinez shot Kershman over a text message she had sent him.

In his appeal, Martinez argued that the trial court erred by denying a motion to suppress statements he made to police. He also said he should not have been found competent to stand trial and that instructions to the jury were flawed.

The high court on Friday found all of Martinez’s arguments were without merit.