A grand jury in Queens decided Thursday not to indict a New York City Police Department detective who fatally shot an unarmed National Guardsman during an October traffic stop on the Grand Central Parkway.

Noel Polanco, 22, was shot by Detective Hassan Hamdy of the Emergency Services Unit after he was pulled over for erratic driving on the parkway near LaGuardia Airport on October 4.

Hamdy told authorities that Polanco reached under his seat when he was asked to put his hands up, but a passenger in Polanco's car disputes that claim.

The lawyer for Polanco's family, Sanford Rubenstein, said in a statement that his clients were "extremely disappointed" at the jury's decision.

"There are a number of things to be considered," Rubenstein said. "First of all, the possibility of the federal government getting involved in terms of the U.S. Attorney's Office, police disciplinary proceedings, as well as the possibility of civil litigation."

Both Polanco's family and National Action Network officials say in separate statements that they will continue a "quest for justice," and Rubenstein said the two groups are meeting on Saturday.

The Queens district attorney said that his office conducted a thorough and independent investigation into the case, and said it cannot comment on the grand jury's findings.

Officer Hamdy will remain on desk duty as the police department finishes its internal investigation.