NEW YORK — The manslaughter trial of a Brooklyn cop who killed four with his minivan after a full day of drinking began Monday with emotional testimony from the husband who lost his entire family.

"First they told us that Dilcia [his sister-in-law] was dead. Moments later, they told us Maria [his wife] was dead," Victor Herrera, 26, testified through tears. "Maybe an hour after that, they told me that my son [Andy] died."

In the time it took 14-year NYPD veteran Joseph Gray's car to plow through the intersection of 46th Street and Third Avenue in Brooklyn, Herrera's family was nearly destroyed. But Herrera, whose wife Maria, 23, was close to giving birth to another son, testified Monday that he still held out hope: That evening, doctors removed the couple's unborn son by emergency caesarian section.

Former NYPD Officer Joseph Gray faces 15 years in prison.

The hope was short-lived, Herrera went on, his voice wavering and his eyes glued to his fidgeting hands.

"I had to make a decision to take off the oxygen," Herrera, a carpenter from Guatemala, told a rapt courtroom audience at the Supreme Court in Brooklyn. "Because they couldn't save him. I held him for an hour and he passed away."

Gray, 41, sat motionless through the re-telling. The officer, who has admitted that he spent the day drinking with fellow cops in the parking lot at the 72nd Precinct stationhouse and then at an off-limits strip club called "Wild, Wild West," faces four charges of manslaughter, four charges of vehicular manslaughter, two counts of driving while intoxicated and numerous other traffic violations.

If convicted, Gray could spend up to 15 years in prison. Since his arrest he has been living at home in Staten Island after posting $250,000 bail.

In his opening statement Monday, Gray's lawyer, Harold Levy, told the jury that even though his client had been drinking, the accident was unavoidable.

"In a flash, people ran from his left to his right, " Levy said. The lawyer slapped his fist into his open palm as he continued. "He hit the brakes as fast as he could … and tragically these people were killed."

Assistant District Attorney Joseph Petrosino urged jurors to hold Gray responsible for his actions. "At 9 p.m. that day, (the victims) were plunged into the horror of an awful death," he said in his opening statement. "The defendant was drunk, irresponsible and reckless … (and) as a result of the choices that he made that day, he brought that family to a violent death."

Petrosino said he will prove using eyewitnesses and testimony from an accident reconstruction expert that Gray ran a red light and was traveling at a pace well over the speed limit of 30 mph. The lawyer also said he plans to call a blood alcohol expert who will calculate that Gray's blood alcohol content at the time of the crash could have been as high as .23, more than double the legal limit of .10 in New York.

Maria Pena lost two daughters and two grandsons.

The matriarch of the victims' family, Maria Pena, who lost two daughters and two grandsons in the collision also testified on Monday, recounting how she walked from her nearby home to the accident scene.

"What happened?" Maureen McCormick, an assistant district attorney asked.

"An accident," said Pena, shaking her head and speaking through an interpreter. "A very terrible thing."

Pena told the packed courtroom, which included an entire row of members from the victims' family, that she expected her daughters and grandson home from a shopping trip to Sears. They never returned home.

The crash occurred on Aug. 4, 2001, on a Saturday evening when it would be common for families in the mostly immigrant neighborhood of Sunset Park to sit out on their stoops.

Joseph Gray was driving his family minivan home after he day of binge drinking with other officers from his 72nd Precinct stationhouse. He had finished his night shift 13 hours earlier and the night ended at a local strip club — an establishment the 72nd Precinct officers were forbidden to visit because it falls in the same neighborhood they are charged with protecting.

Rosa Cintron, 26, was sitting on her porch overlooking the intersection where the accident occurred when she saw Maria Herrera, her sister, Dilcia Pena, 16, begin to cross at the crosswalk, with 4-year-old Andy, Maria's son, in tow. Two other witnesses testified Monday that they believe the family was crossing with a green light.

"As they started walking and got to the middle lane, a car came out of nowhere and they got hit," Cintron testified. "I see one sister in the air as high as the BQE," she said, referring to the elevated expressway above the avenue. "I was hysterical."

Cintron sobbed as prosecutors played a tape of the 911 call she made that evening. Relatives of the victim sitting in the back of the courtroom echoed her cries.

"Oh, my God, oh, my God, oh, my God," Cintron can be heard screaming on the tape. "Ma'am, you have got to calm down," the operator says.

On Tuesday, Petrosino says he will call a series of police officers, including NYPD Captain Bryan White, a longtime friend of Gray's who responded to the accident scene. That night, White took Gray into the back of his patrol car and asked him: "Just between me and you, Joe. I have to know if you've been drinking."

"I am glad it is someone like you, Bryan," Gray told his friend. "I know I will get a fair shake. I have got to admit I was drinking, but it was earlier. I was on my way [home] and they darted in front of me."