The case of a Long Island man who claims he was wrongly convicted of murdering his parents is a classic example of a false confession, two experts on police interrogation say.

Their views are cited in court papers being filed today by lawyers seeking to free Martin Tankleff, who was imprisoned for killing his mother and father in 1988, when he was 17.

Mr. Tankleff has denied guilt and accused the police of tricking him into a false admission. A retired detective, K. James McCready, later acknowledged lying to him, including saying that his wounded father had identified him as his attacker. Mr. McCready also wrote an admission, which Mr. Tankleff never signed and immediately disavowed. .

That confession was erroneous, "coerced" and "inherently unreliable," said Dr. Richard J. Ofshe, a sociology professor at the University of California at Berkeley who has researched false confessions and testified in dozens of cases. Dr. Richard A. Leo, a criminology professor at the University of California at Irvine, called the confession "almost certainly false."

The Suffolk County district attorney's office, which opposes the Tankleff appeal, declined to comment until it reviews the brief.

From the start, Mr. Tankleff has implicated his father's former business partner, Jerard Steuerman, who owed hundreds of thousands of dollars and was the last person to leave the house that night. Mr. Steuerman has denied involvement.

Now a new witness, Glenn Harris, says he took two men to the house late that night. One had connections to the Steuermans and told people he had been involved in the killings, though he now denies it.

Dr. Ofshe said the police had used tactics like isolation and trickery, which can produce false confessions. They removed Mr. Tankleff from relatives, friends and lawyers, promising to take him to the hospital.

Instead, he was interrogated for hours in a small room. The police dismissed his denials. According to testimony, they also lied, saying that his hairs had been found on his mother's body and that a humidity test proved he had taken a shower to wash away the blood. They suggested that he had suppressed memory of the crime, and finally he relented.

None of the evidence fit, Mr. Tankleff's lawyers say. The confession said the weapons were a knife and dumbbell, but no blood was found on them, and medical experts found hammer wounds. The confession said Mr. Tankleff had washed off the blood, but none was found in the shower drain.

The confession said he fought with his mother, but he had no scratches or bruises and no blood or skin under his nails.

The confession said he first killed his mother in her bedroom, then attacked his father in the study. But according to court documents the father's blood was found in the bedroom, indicating the reverse order.

"These numerous discrepancies," Dr. Ofshe said, " strongly suggest that the narrative was not the product of Mr. Tankleff's personal knowledge of the crime."