A New York prosecutor says an ex-convict feared being caught with a handgun when he shot to death a police officer, and then escaped by killing a second man during a carjacking.

Opening statements began Monday in the first-degree murder case of 34-year-old defendant Darrell Fuller. He is charged in the 2012 shooting deaths of both Nassau County Police Officer Arthur Lopez and Raymond Facey, who was killed during a carjacking moments later.

Authorities say Lopez chased Fuller because he suspected Fuller had been involved in a hit-and-run. The prosecutor says Lopez approached Fuller armed with a Taser and that Lopez got within about 5 feet of Fuller when he opened fire.

Fuller's attorney has asked jurors to be skeptical of the prosecution case.