A Manorville man pleaded guilty Thursday to killing his friend while driving drunk last year.

Because of "some proof issues about who was actually driving the car," state Supreme Court Justice Fernando Camacho said he approved a plea deal in which William Christie, 70, will serve 9 months in jail and 5 years on probation in return for his plea to aggravated vehicular homicide. The charge carries a maximum sentence of 8 1/3 to 25 years in prison.

Assistant District Attorney Elizabeth Miller said in court that she explained the weaknesses in the case to the family of the victim, Michael Demartino, 59, of Manorville.

"This [deal] is acceptable to the family," Miller told Camacho.

During questioning by Camacho, Christie said his blood-alcohol content was over .18 percent -- more than double the legal standard of .08 percent -- when he lost control of his Jeep on Feb. 26, 2014, killing Demartino.

Camacho will sentence Christie Aug. 12.

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Afterward, Assistant District Attorney John Scott Prudenti said the case would have been difficult to prove to a jury at trial because it initially appeared to police that Demartino was the driver. Neither man was wearing a seat belt as they headed home after a night out drinking.

When Christie's Jeep flipped on Sunrise Highway near Exit 59 in Manorville, Christie was ejected and Demartino's body ended up behind the steering wheel of the upside-down sport utility vehicle.

"This is a unique situation, complicated by the fact that the victim and the defendant were out, as to their usual custom," Prudenti said. They had spent much of the evening drinking at Buckley's Irish Pub in Center Moriches.

Further investigation found Christie's DNA in a part of the car that showed he was the driver, Prudenti said.

Both Christie and his attorney, Eric Sacks of Bellmore, declined to comment on the guilty plea Thursday.