The Utah Court of Appeals has rejected claims by a man that his life conviction for shooting a woman multiple times in the back and dumping her body in the Jordan River should be overturned.

In its ruling issued Thursday, the appellate court upheld the conviction of Darius Pena Malaga, 24, on charges of murder, aggravated kidnapping, aggravated robbery and conspiracy for which he received 30 years up to life in prison.

Malaga had claimed that jurors were not adequately instructed on how to treat the testimony of key witness and co-defendant Silia Olive, 24. Malaga claimed Olive was testifying to save her own skin. Olive was sentenced to 20 years to life for criminal homicide and aggravated kidnapping.

The court of appeals concluded that Malaga had approved jury instructions just before the trial and that there were no "exceptional circumstances" to show any significant oversight by Malaga's trial attorney.

Malaga was convicted by a jury in the shooting death of 22-year-old Amy Tavey. Prosecutors said Malaga killed Tavey out of frustration because the person he set out to kill got away.

According to police, on May 3, 2002, Olive and a minor friend lured Keith Williams and his girlfriend, Tavey, to Olive's home to kidnap, assault and murder Williams for something he had done to anger Malaga. At the home, Williams was beaten, robbed, tied up with duct tape and forced into the trunk of his car. Tavey was taken in another car, and both vehicles were taking the couple to another home located near the Jordan River.

While en route, Williams managed to pop the trunk and escape unnoticed. When Malaga and Olive arrived, Malaga noticed Williams had escaped. Police say he then pulled Tavey from the car and led her away by the arm. A few minutes later, Olive testified that she and a friend heard multiple gun shots. Tavey's body was found the next morning floating in the Jordan River with multiple gunshot wounds in the back.

The court of appeals also addressed Malaga's claim that he should have received credit for the support of his family at the time of sentencing. The appellate court found that despite Malaga's claims of family support, no letters were ever submitted to the court on his behalf and that his attempts to contact family members were not successful.