Spota said Grasing ran two red lights in his 2004 Nissan Maxima, drove on the sidewalk, and wove in and out of traffic, even into oncoming lanes, before ramming the Kia Sportage driven by Brittney Walsh, 18.
Judge Patricia Filiberto set bail at $100,000 cash or $200,000 bond at Grasing's arraignment Wednesday in First District Court in Central Islip. He pleaded not guilty to driving while intoxicated, a misdemeanor.
Assistant District Attorney Laura Newcomb said upgraded charges are expected to be filed as new evidence is developed.
A blood sample taken 11/2 hours after the crash showed Grasing had a 0.30 percent blood-alcohol level, Spota said. The legal limit is 0.08 percent.
Grasing was charged with DWI in upstate Albany County in 1999, and pleaded guilty to a lesser charge of driving while impaired, officials said.
Newcombe said in court that Grasing has been "in and out of rehab, and he's gone on benders where he's disappeared for days."
Defense attorney William Keahon disputed that assertion. He said Grasing has worked as a contractor for 10 years with his father.
The defendant has a 3-year-old daughter and lives with his wife, Keahon said.
"The prosecution thinks they have a strong case. I do not," Keahon said in court.
The attorney said afterward that Grasing's family is "devastated at the death of a young girl."
Officials are asking anyone who may have seen Grasing's vehicle or the crash to call police at 631-854-8152.
Spota said investigators are especially interested in talking to the driver heard yelling at Grasing by witnesses.
"Any father would be lucky to have her as a daughter. Any teacher would be lucky to have her as a student," Casale said.
"We hugged her on Friday, and we have to bury her this Friday," Gusmano said. "My son is angry. The feeling I'm getting from everybody is that everybody's very angry. It's senseless."
Walsh was also remembered for her efforts to keep alive the memory of her best friend and classmate, Christopher Urban, who died in October 2010 from a congenital brain condition.
With Joseph Mallia,
John Valenti, William Murphy and Nathaniel Herz