The driver who allegedly fled the scene of a car crash that killed three of his friends in Olney Sunday had been to two parties before the incident, and he smelled of alcohol when detectives tracked him down about three hours later, Montgomery County’s top prosecutor said Monday.

Montgomery State’s Attorney John McCarthy said investigators are awaiting the results of a blood test to determine if Kevin Coffay, 20, of Rockville, was intoxicated when he swerved off Olney Laytonsville Road and struck two trees and a telephone pole early Sunday morning.

McCarthy said the surviving passenger, Charles A. Nardella, 19, of Gaithersburg, told detectives Coffay had been to two parties that night and had been drinking. The man also told detectives Coffay ran into the woods almost immediately after the wreck.

“He could not believe he just got out of the car ... leaving them all,” McCarthy said.

Three young people died in the crash. Haeley N. McGuire, 18, was a senior at Magruder High School in Rockville, Coffay’s alma mater. Spencer Datt, 18, of Derwood and John Hoover, 20, both of Rockville, were Magruder graduates.

Nardella was treated at a hospital for injuries that were not thought to be life-threatening, authorities said.

The new details emerged at a bond hearing Monday in Montgomery County District Court in Rockville. In front of a courtroom packed with friends and classmates of Coffay and the victims, Judge William G. Simmons eventually ruled that Coffay’s family could post 10 percent of the original $500,000 bond to get Coffay out of jail. McCarthy had asked the judge to keep the bond at $500,000, arguing that Coffay twice fled from officers who spotted him and yelled for him to stop.

Detectives found Coffay about three hours after the crash, when a friend drove him back to his family’s house in Rockville, McCarthy said. He said Coffay’s eyes were watery and bloodshot, and he smelled of alcohol. Coffay was arrested and charged with failure to immediately return and remain at the scene of an accident involving bodily injury and other related counts, authorities said.

People who knew those involved in the crash said the four men had all graduated from Magruder High in Rockville and gone on to college. Haeley McGuire was a senior who was about to graduate and start college, friends said.

Michael J. McAuliffe, Coffay’s attorney, said at the hearing that Coffay acted as any “panicky young man” would when he left the scene of the crash, and he “wasn’t a guy who was taking off.”

McAuliffe aid Coffay, a James Madison University student, might need treatment for depression. He said Coffay’s 58-year-old father had recently moved in to a facility for treatment of advanced Alzheimer’s disease and his mother has cancer.

McCarthy painted a somewhat less sympathetic picture, saying that when he was in police custody, Coffay said: “They were all fine when I left.”

This post will be updated.