DENVER (AP) - The family of slain Columbine student Daniel Rohrbough claims a Denver police officer killed the boy as he fled the massacre inside the school. A motion filed Wednesday in federal court said Sgt. Dan O'Shea, a member of the SWAT team during the April 20, 1999, shootings, was identified through testimony by a school administrator, Celine Marquez, who said O'Shea told her two days after the shooting that he feared he may have shot an innocent student. The motion asks a judge to reconsider the dismissal of a lawsuit brought against the Jefferson County school district and sheriff's office. Brian Rohrbough has long claimed his son was shot by a lawman rather than by one of the student gunmen firing from inside the school because of the angle of his fatal chest wound. In all, 12 students and one teacher at Columbine High School in Littleton, a Denver suburb, were killed before attackers Eric Harris and Dylan Klebold killed themselves. According to the motion, O'Shea's handwritten police report stated he shot a 9 mm machine gun from the base of a hill on which Rohrbough was shot and killed. Rohrbough's wounds were consistent with the student facing downhill and O'Shea firing from below, the motion said. The court papers said Marquez was visiting Westridge Elementary School on April 22, 1999, when she encountered O'Shea, whose daughter attended preschool at Westridge. According to the motion, Marquez thanked O'Shea for responding to the attack at Columbine. O'Shea broke down crying, saying he had thought he might have mistakenly shot an innocent student, the motion said. He told her he was relieved to learn that ballistics tests showed none of the victims had been struck by police bullets, it said. Lawyer Barry Arrington, who represents the Rohrboughs, said Wednesday that in fact, ballistics tests on the bullets had not been started when O'Shea spoke to Marquez. "Someone told Sgt. O'Shea a grievous lie," he said. O'Shea could not be reached for comment Wednesday, the Rocky Mountain News and The Denver Post reported. Denver Deputy Police Chief Dave Abrams said Wednesday that he was unaware of the accusation against O'Shea. "I think it's unlikely," he said. "I would seriously doubt it." The motion also accuses Sheriff John Stone and his department of making 29 "blatant, bald-faced lies" about the investigation, including initially identifying a bullet recovered from Rohrbough's body as one from Klebold's weapon. Brian Rohrbough said he didn't know about Marquez's story until a few days before a federal judge dismissed all but one of the Columbine wrongful-death suits last month. After the ruling, he asked Marquez if she would give a statement. Marquez said she frequently told the story of her meeting with O'Shea, and "I felt I was relaying a hero's story." According to the motion, sheriff's deputy Jim Taylor said that a Denver police officer was near him in the lower student parking lot during the massacre and that he remembers hearing machine gun fire and seeing a boy, later identified as Daniel Rohrbough, get shot.