An Albuquerque police officer and retired detective who killed a homeless man last year pleaded not guilty Friday to second-degree murder charges stemming from the on-duty shooting death that unfolded after a standoff, reports the Associated Press.

Officer Dominique Perez and now-retired Detective Keith Sandy entered their pleas at a hearing in New Mexico's Second District Court.

A judge ruled last month there was probable cause for the men's case to go to trial. The decision followed a two-week preliminary hearing in which Special Prosecutor Randi McGinn argued evidence that James Boyd was shot in the side and back indicated he posed no threat to officers when he was killed.

Perez and Sandy could face up to 15 years in prison if convicted of second-degree murder. A voluntary manslaughter conviction carries a term of up to three years.