GREAT NECK, N.Y. — The letter to the Nassau County district attorney’s office was succinct and unambiguous.

“I write to inform you that none of the events allegedly described by or attributed to Kenneth Doe ever took place,” a man in his 30s wrote last month, referring to his role a quarter century ago as one of the children whose allegations of sexual abuse sent three men to prison, fueled a panic in hundreds of families and were later portrayed in the 2003 documentary “Capturing the Friedmans.”

In the letter, the man said that neither Arnold Friedman, who in the 1980s ran a computer class at his house in this affluent Long Island suburb, nor Mr. Friedman’s son Jesse, who sometimes helped him, had sodomized him, touched him inappropriately or shown him pictures of naked people. He had never observed either of them engaged in anything “even remotely akin to sexual conduct.” He had no reason to believe any such acts occurred. What he did remember was that the police repeatedly came to his house to question him and would not leave until he gave them the account of sexual abuse they wanted.

“As a result,” his letter said, “I guess I just folded so they would leave me alone.”

He is one of several key figures who have recanted or disputed parts of accusations attributed to them in the Friedman case, the subject of an almost three-year investigation by the Nassau County district attorney’s office following a withering 2010 ruling by the United States Court of Appeals for the Second Circuit. The court said that it could not overturn Jesse Friedman’s conviction because the appeal came too late, but that there was “a reasonable likelihood” that Mr. Friedman was wrongfully convicted. It suggested that the Nassau County district attorney, Kathleen M. Rice, reinvestigate the case to determine whether Mr. Friedman’s conviction should be upheld or overturned. Ms. Rice has said she will release a report by June 28.