Cop: DeFeo Altered Story By Don Smith -Less than two hours after he had become a suspect in the murders of his family, Ronald DeFeo Jr. changed his story, telling police, "It just started.- It went SO fast, I just couldn't stop." At first, he had insisted that he didn't see or hear anything on the night of the slayings. That's what Homicide Squad Det. Dennis Rafferty told the jury in State Supreme Court yesterday. Rafferty said that at one point DeFeo had told him that he could visualize his brother's foot twitching after he was shot. "That indicated to me he had to have been there, and I pressed him and he said he did it alone," Rafferty testified. Earlier, Det. George Harrison, under questioning by prosecutor Gerard B. Sullivan, said that DeFeo went to sleep last Nov. 13 on a Homicide Squad cot as a sympathetic figure, the sole survivor of a mass murder, whose life might have been in danger from mob figures. But by the time DeFeo awoke at 9 the next morning, Harrison said, the young man had become a suspect. Two cardboard rifle cases had been found in his room, a .35-cal. Marlin bullet had been found near one of the bodies, and friends of DeFeo's had told police he was a gun buff who knew all there was to know about weapons. The night before, Harrison testified, DeFeo had said that he had a .22-cal. rifle; a pellet gun, and once had a rifle, but didn't know what caliber it was. Harrison told the jury that, after DeFeo awoke, he was informed of his rights, but waived them, saying that he wanted to cooperate with the police. Harrison testified that DeFeo admitted to injecting himself with heroin the day the bodies were found, burglarizing a vacant house on his block, and setting his father's boat afire to get insurance money. DeFeo's court-appointed lawyer, William Weber, has insisted that the confession was beaten out of DeFeo by police after the suspect had been grilled without food or sleep for 30 straight hours, and after Richard Wyesling, an attorney and a relative, had -Continued on Page 43