The Utah Court of Appeals has upheld the first-degree murder conviction of a 36-year-old Orem man in a 1995 slaying stemming from a drug dispute.

The three-judge panel also affirmed Thursday the 5-years-to-life prison sentence Robert E. Dillenbeck received for throwing Fernando Olivas from a moving car near west Salt Lake's Pioneer Park.Prosecutors said that after attempting to retrieve cocaine, Olivas was assaulted by Dillenbeck and thrown from his car, which was traveling at between 10 and 20 mph. Olivas died at the scene.

Dillenbeck said he acted in self-defense and that he felt threatened by Olivas, who was carrying a knife in one of his pockets.

Among other things, Dillenbeck argued in his appeal that the trial court had erred in not including a cautionary jury instruction regarding the testimony of an informant and that there was insufficient evidence to convict him.

Dillenbeck also alleged prosecutorial misconduct, citing a cross-examination in which Dillenbeck's refusal to testify was noted.

In a decision written by Judge Norman H. Jackson, the appellate court found that the prosecutor's comments would not "naturally and necessarily be construed by a juror as a comment on the defendant's silence."