Keith Allen Green lay in wait in a thicket of trees for 13-year-old Claudia Pickeral to walk home from the school bus stop before he tried to rape her, bludgeoning and strangling the girl, the prosecution alleged yesterday in opening statements at his murder trial.

Green's trial in the 1997 slaying of the Leonardtown Middle School student opened in Prince George's County Circuit Court and included testimony from Claudia's mother and two people who saw a man dragging the child's body across the road.

Green, 35, a former pool installer, once lived next door to the seventh-grader's family in Longview Beach, a rural waterside community in St. Mary's County. He was indicted on kidnapping and first-degree murder charges last September.

Although the slaying occurred in St. Mary's County, the trial was moved to Prince George's after a judge ruled in February that the case and its complicated aftermath were so familiar to the 83,000 residents of St. Mary's that it would be impossible to find an untainted jury.

St. Mary's County State's Attorney Richard Fritz said yesterday that on Feb. 19, 1997, "Keith Allen Green decided he was going to have sex with Claudia Pickeral." When she would not consent, Fritz said, "there was a struggle."

Claudia, Fritz said, was killed by a combination of blows to her face and head and strangulation.

Green's attorney, Julian Izydore, of Leonardtown, said in his opening remarks that the state lacks physical or forensic evidence linking his client to the crime. Green, dressed in a tan suit, sat quietly at the defense table, his mother and another relative sitting behind him.

Izydore scoffed at the prosecution's use of witnesses who would testify that they saw Green wearing red sweat pants and a white T-shirt on the day before the killing, the same attire as the man seen dragging the body along the road. He argued that Green's odd comments to sheriff's detectives the next day--including one remark about his "ruined" life--meant nothing.

"Keith Green didn't commit this murder. He wore red sweat pants and a white T-shirt the day before the murder," Izydore said. "And he made suspicious comments [to sheriff's detectives] the day after the murder. That's all there is."

Moreover, Izydore said, sheriff's detectives failed to investigate a male friend of Claudia's who had spent time at her house in the days before the attack. The friend, a Great Mills High School student, told police that he was in school the day of the slaying, but attendance records said otherwise, Izydore said.

In later testimony, Harriette Johnson, of Landover, a part-time Washington Post Co. telephone systems employee, told jurors that she and a friend were in the area scouting vacation property when she saw a man dragging a child across the road. She and her companion went to investigate, she told the jury, and "when the person saw us coming, he dropped the arm of the child. . . . He looked up and took off down the hedges of the house."

Johnson described the man as wearing red pants and a white shirt, as having light brown skin and standing between 5 feet 7 and 5 feet 9 and weighing 185 to 200 pounds. When Fritz showed her a small photo of Green yesterday, she was not able to say for sure whether he was the child's attacker.

Johnson and her friend drove frantically, trying to find an occupied house amid the vacation properties so they could ask to use the phone to call police. The home they came to was Claudia's.

The police were summoned. Claudia's mother, Claudia Thompson, 31, an aide in a Head Start program, told the jurors what happened next.

"I went racing down the road looking for her," Thompson said. She spotted her lifeless child lying in the driveway of an empty home. A neighbor was already attempting cardiopulmonary resuscitation.

"Her clothes were all disheveled, all over the place," Thompson said in a flat voice. "She had bruises on her forehead and on her cheek. She had hand marks around her throat."

The state is expected to continue its case tomorrow. The trial is expected to last two weeks.