Charges against 27-year-old Christopher Bouchard, of Mastic Beach, were upgraded to second-degree manslaughter and criminally negligent homicide.
He was previously charged with just reckless endangerment, but Suffolk County prosecutors convened a grand jury to consider higher charges. They came back with the five-count indictment after hearing from a dozen witnesses and reviewing evidence from a crash reconstruction and crash reenactment.
Bouchard pleaded not guilty in court in Central Islip Monday.
Investigators believe he intentionally struck 20-year-old Anthony Garriques and 19-year-old Keenan King with his minivan.
The dirt bike had been reported stolen earlier in the day from the garage of Bouchard's home, and police say he later heard from a friend who reported seeing the bike in Bellport.
Authorities say Bouchard and his brother went to Bellport to search for the bike, and soon thereafter a chase ensued that ended when Bouchard rear-ended the dirt bike on Montauk Highway. The police investigation found Bouchard operated his van at a high rate of speed, failing to maintain his lane and at an unsafe distance during the chase.
The families of the victims, who were present in court, have been calling for charges to be upgraded.
They became loud and emotional when the new charges were added and had to be ushered out of courtroom. They are reportedly unhappy with the upgraded charges, saying they wanted murder.
Bouchard is being held on $400,000 cash or $800,000 bond.