The trial of Jason Lee, a former Goldman Sachs managing director accused of rape in a 2013 incident in East Hampton, began Wednesday in the Riverside courtroom of acting State Supreme Court Justice Barbara R. Kahn. Mr. Lee waived his right to a jury trial last week.Kerriann Kelly, head of the Suffolk County District Attorney's major crimes division, gave an opening statement for the prosecution. Andrew Lankler of Baker Botts, a law firm headquartered in Houston, spoke for the defense. He is representing Mr. Lee, along with Edward Burke Jr. of Sag Harbor.Ms. Kelly pointed at Mr. Lee as she began addressing the court. The man seated at the defense table, wearing a dark, tailored suit, hair carefully combed, taking notes was not, she said, the same Jason Lee whom his young Irish accuser, identified only by her initials, D.D., had tried to fight off in the early morning hours of Aug. 20, 2013."Sometimes, your honor, what you see is not what you get," Ms. Kelly said. When D.D. and her brother, Colin, along with two friends, met Mr. Lee and his friend Rene Duncan that night, there was "a clash of two worlds so far apart, they might as well be different planets," she said.After the party left Georgica, a Wainscott restaurant where they had met, Mr. Lee stripped naked, Ms. Kelly told the court, while D.D. and a friend, Fiona, were swimming "in their knickers" in the pool behind a Clover Leaf Lane house he had rented for the summer. When he entered the pool, she said, the women got out.Ms. Kelly continued: When D.D. went into a bathroom to change back into the dress she had been wearing that night, Mr. Lee, still naked, forced his way through the door so hard that she was sent flying backward, suffering injuries. "He pulled down her dress and pulled down her underwear," the prosecutor said, and then raped her. Ms. Kelly fixed Mr. Lee with a steady glare as she spoke.Mr. Lankler painted a different picture for Justice Kahn. "You will never know beyond a reasonable doubt what happened between my client and the claimant," he began. He said that what had occurred was "consensual sex. Perhaps regrettable consensual sex, but consensual sex."It was not believable, he continued, that Mr. Lee could have raped the woman in a bathroom about 12 to 15 feet away from where her brother and her friend were seated in the living room. "Mr. Lee had photos taken of every inch of his body," said Mr. Lankler, without a scratch or a bruise being found."You are never going to know what happened that night," he repeated.Ms. Kelly had described what happened after police were called. Officer Sarah Mortensen of the East Hampton Town Police Department, the first on the scene, found Mr. Duncan running up and down the street, yelling that his vehicle had been stolen, when Colin, the alleged victim's brother, approached her. He got into the squad car with her and told her that something had happened to his sister.Police then searched the house and the surrounding area, Ms. Kelly told the court, looking for the summer dress D.D. had said she was wearing when she was raped. They never found it, she said. Seven months later It was brought to the district attorney's office by a representative of the defense team.Mr. Lankler countered that during a pre-trial hearing, D.D. had contradicted herself about whether she was wearing the dress.Following the opening statements, the prosecution introduced its first piece of evidence, a recording of Mr. Duncan's 911 call to the police, reporting his vehicle stolen. The call had come in at 6:24 a.m. In it, Mr. Duncan sounded unable to follow simple questions, slurring his words repeatedly, then hanging up.Stephen Blanchard, a police dispatcher, called him back, requesting a description of the missing vehicle. At one point, Colin took the phone, also slurring his speech. He told the dispatcher that "I've got another situation I've got to sort out."Officers Mortensen and Lisa Weitz were next to the stand. Officer Mortensen said that when she arrived, she had been told to investigate a “disturbance” and a possible theft of a vehicle. Mr. Duncan and Mr. Lee were in the street, along with the three Irish students. Mr. Lee, she said, came over to the passenger window and told her that everything was under control, and police were not needed. But, at the same time, Mr. Duncan was still yelling, saying his vehicle had been stolen.That is when D.D.’s brother approached the officer, saying he needed to talk. Getting into the police car, he told her something had happened to her sister, the officer testified. Colin got out of the car, and D.D. got in. She told the officer she had been raped, and the investigation began.At one point, a Lindy’s Taxi arrived. The driver told an officer the company had received a call to pick someone up. With the beginning of an investigation into the rape allegation, the officer sent the cab away. At about that time, an officer noticed Mr. Lee had disappeared..An officer took all three students to police headquarters, after Officer Weitz arrived.Officer Weitz testified that Mr. Duncan told her nobody was in the house then went inside. It sounded to her like he was arguing with someone on his cell phone or perhaps someone in the house.Officer Weitz said the parking lights flashed on the Range Rover. Another town police officer drove up, and Officer Weitz had him park behind the Range Rover.After checking inside of the house, Officer Weitz came out, and looked through the front window of the Range Rover. While all the other windows were heavily tinted, she could see through the front, she said.In the back seat, curled up into a fetal position, she said, was Mr. Lee. By then it had been two hours since Officer Mortensen had first noticed him missing.Mr. Lankler’s cross examination of the two officers was brief, though he spent a bit more time with Officer Weitz. He had both read from their grand jury testimony, made just days after the incident.The trial resumes Thursday at 10:30 a.m., and and is expected to run through next week.