Tyrone Howard pleads not guilty in case of slain NYPD officer

The man accused in the fatal shooting of an NYPD detective has pleaded not guilty to first-degree murder charges.
Police say Tyrone Howard is accused in the death of Detective Randolph Holder, killed last month in the line of duty. 
They say Holder was responding to a report of shots fired and a stolen bicycle in East Harlem when he was struck in the head. 
Prosecutors say Howard knew Holder was on the force when he pulled the trigger, and was recently sentenced to 12 years in prison on an unrelated drug charge.