An off-duty Suffolk County police officer drank 10 pints of beer and a margarita at a bar with fellow officers before driving the wrong way on Sunrise Highway and killing another motorist, Suffolk District Attorney Thomas Spota said Wednesday.

Spota provided the new details in support of upgraded charges against Officer Robert Scheuerer, 24, who pleaded not guilty.

Scheuerer made his first public appearance since the Sept. 27 crash in West Islip. He arrived at the Central Islip courthouse in a wheelchair, missing his left leg below the knee.

He is now charged with aggravated vehicular homicide, several lesser homicide charges, second-degree reckless endangerment and aggravated driving while intoxicated. Scheuerer faces a maximum of 9 1⁄3 to 26 years in prison if convicted of all charges.

Assistant District Attorney Marc Lindemann said Scheuerer’s sport utility vehicle collided with a van driven by Brian J. Fusaro, 37, of Bay Shore. The van exploded and Fusaro, who was on his way to work, burned to death.

In part because of Scheuerer’s injuries, Lindemann said he was no flight risk. State Supreme Court Justice Fernando Camacho allowed Scheuerer to remain free on bail of $250,000 bond.

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Before the arraignment, about two dozen police officers who showed up in support of Scheuerer briefly jostled news photographers and videographers outside the courthouse and in the hallway outside the courtroom.

Spota said Scheuerer and other officers spent hours at a bar near the Third Precinct in Bay Shore, where he is assigned. Scheuerer got there about 10 p.m. and left at 2:49 a.m., the district attorney said.

The crash happened two hours later. Spota, who declined to name the bar, said Scheuerer went the wrong way on Sunrise Highway — driving west in the eastbound lanes — for probably less than two miles.

Outside the courtroom, Scheuerer’s attorney, William Petrillo of Garden City, said his office found evidence that other factors besides his client’s alcohol consumption led to the crash. He would not describe that evidence.

Scheuerer “is very much concerned for the family of the victim in this case,” Petrillo said.

The officer, on the force for a year, has been suspended without pay.

Spota said Wednesday that Scheuerer had a blood-alcohol level of 0.174 percent — more than twice the legal threshold of 0.08 percent — one hour and 14 minutes after he crashed his 2000 Nissan Pathfinder into the 2016 Ford van.

An estimation technique known as retrograde extrapolation allowed prosecutors to conclude that Scheuerer’s blood-alcohol level was 0.19 percent at the time of impact. The threshold to prove aggravated vehicular homicide is 0.18 percent.

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But Petrillo said retrograde extrapolation “is an extremely unreliable scientific method” and any charges related to the 0.18 percent threshold won’t be proved.

Spota said his office considered a second-degree murder charge but ruled it out after comparing the case to one involving Christopher O’Brien, 55, of Sound Beach.

Prosecutors say O’Brien, on Dec. 23, 2015, drove seven miles the wrong way on Sunrise Highway and numerous motorists tried to warn him before he crashed, killing another motorist, Thomas D’Eletto, 57, of Aquebogue.

Spota said the unheeded warnings were evidence of depraved indifference to human life, necessary for a murder charge. O’Brien is awaiting trial on second-degree murder and other charges.

An off-duty Suffolk police officer was arrested in September after he drove the wrong way on Sunrise Highway in West Islip and crashed into a van, killing the driver, police said. Robert Scheuerer, 24, who prosecutors allege was drunk at the time of the crash, pleaded not guilty in court on Wednesday, Dec. 13, 2016. Photo Credit: Paul Mazza

O’Brien’s attorney, Scott Gross of Garden City, however, argued that the cases are virtually the same.

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“Contrary to any recent statements, there does not appear to be any difference in the allegations,” Gross said. “It leaves one to question why there is a difference in the charging decision.”