Police Commissioner Raymond W. Kelly said that the moments leading up to last week’s fatal shooting of an unarmed motorist on the Grand Central Parkway in Queens remained unclear, and warrant grand jury scrutiny.

“It will require what I believe to be a grand jury investigation to determine precisely what happened there,” Commissioner Kelly told reporters Monday just before joining the Columbus Day parade.

The Queens district attorney, Richard Brown, has already said that his office is investigating the shooting of Noel Polanco during an early morning traffic stop last Thursday. It is routine procedure for prosecutors to bring fatal shootings by the police before a grand jury.