The seven-man, five-woman panel has deliberated for four days before giving up on Friday.
Wednesday, after more than seven hours of deliberations, the jury sent a note to Superior Court Judge William Forester that apparently indicated a deadlock.
But the judge ordered the jurors to go back and try again to reach a verdict.
Kenneth Powell, 40, of Pennsville, was charged with manslaughter, vehicular homicide and aggravated assault by auto in a July 22, 2000 collision that killed two people and critically injured a third person. He faced 15 years in prison if convicted.
Powell wasn't in either of the cars involved in the crash. But his friend, Michael Pangle, was at the wheel of the car that caused the accident - which killed him as well as a man in the second car.
The case - the first of its kind - was being watched closely around the nation for any legal precedents that may be set. Some predicted this case could have opened the floodgates for virtually anyone to be held criminally liable for not stopping a drunk driver.
Authorities say two years ago - after a night of boozing it up in New Jersey strip clubs - 40-year-old Pangle was pulled over with more than twice the legal limit of alcohol in his system.
Handcuffed in the back seat of a cruiser, Pangle was driven to the New Jersey state police barracks, where a friend was called to pick him up.
That friend was Powell. Prosecutors say that instead of driving Pangle home, Powell chose to drive Pangle back to his car - and began what prosecutors call a game of Russian roulette.
Michael Ostrowski, Assistant Salem County Prosecutor, said "Ken Powell put that bullet in, spun it, cocked the hammer back, handed that gun to Mike Pangle and said, 'Here, shoot it down the road, if it hits somebody so what?'"
Three hours later Pangle was dead. And so was 22-year-old Navy Ensign John Elliott. Elliot's girlfriend was critically injured.
Pangle had hit them head on, after crossing the center line on U.S. 40.
According to an autopsy, Pangle's blood alcohol level was .26 percent at the time of his death.
The state of New Jersey contended Ken Powell's actions allowing Pangle back behind the wheel were so reckless they're enough to throw him behind bars for years.
Some argued that prosecutors are taking things too far.
"This is going to mean that New Jersey can change the name of its license plate from the Garden state to the Vigilante state," said Gary Trichter of the National College of DUI Defense.
"What they are about to decide will ring the bell across this nation on how the government should react to people who are DWI," said Powell defense attorney Christopher Manganello.
The defense claimed that if anyone was responsible, it was the state troopers who released the drunk driver and gave him his keys in the first place.
Said Manganello, "Something is rotten here, where every verifiable fact that we have in court, indicated that Ken Powell did what the troopers told him to do."
The case has already changed New Jersey law. Troopers are now required to impound a drunk driver's car for at least 12 hours after an arrest. The law is named after the navy ensign who died in the crash and his parents are now trying to make it a federal law.
In a 70-minute closing argument to jurors Tuesday, Manganello said Powell was targeted because Pangle is dead and couldn't be held accountable.
"What it boils down to, ladies and gentlemen, is that the state wants their pound of flesh," Manganello said. "Two people are dead and Kristen Hohenwarter is seriously injured. Do we have any doubt who would be sitting in that defendant's chair if Michael Pangle were still here?"
Assistant Salem County Prosecutor Michael Ostrowski told jurors that Powell made a series of conscious decisions that led to the deaths of Pangle and Elliott.
Calling Pangle "a boisterous, obnoxious loudmouth with his stinking breath," he said any reasonable person would have known not to return him to his vehicle in that condition.