A teenager woke up early on the first day of his senior year, strolled into the den and found his father covered in blood.
Marty Tankleff called 911 in a panic, then darted through the sprawling, upscale house to search for his mother. Her blood-splattered body lay on the floor of her bedroom. Hours later, he did the unthinkable: He confessed to killing his parents, even though he hadn't.
Investigators lied about having evidence against him and eventually convinced Marty, who was in shock, that he must have attacked his parents, then blacked it out.
"In my case, the system failed -- from the police to the prosecutors to the court system," said Tankleff, now 39.
The Long Island native spent nearly 17 years in a New York prison before he was released in 2008.
Another teen confession, now under scrutiny, is that of 17-year-old Jessie Misskelley Jr., who has been diagnosed as borderline mentally retarded. He and his friends, Damien Echols, 17, and Jason Baldwin, 16, were convicted of killing three 8-year-old boys in 1993 in a wooded area of West Memphis, in Arkansas.
Defense attorneys are lobbying for a new trial, arguing that new DNA evidence points away from the defendants, and jurors were swayed by a confession that doesn't match the evidence.
All three have won a rare hearing before a new judge, who is expected to decide in December whether to grant a second trial before a jury.
Confessions have long been considered proof of a person's guilt. After all, false confessions defy common sense, said Scott Burns, executive director of the National District Attorneys Association, headquartered in Virginia.
"What reasonable person ... would confess to committing some heinous crime of murdering multiple people if they didn't do it?" Burns said.
But, through DNA advancements since the late 1980s, science has continued to expose dozens of confessions as false. Across the nation, 269 prisoners have been exonerated through DNA evidence -- including 17 former death row inmates, according to an analysis by the Innocence Project, a New York-based nonprofit organization that works to free the wrongfully convicted.
Of 80 exonerations through DNA evidence, nearly 54 percent of those wrongfully convicted had falsely confessed to murders they didn't commit, according to the Innocence Project.
That's what happened to New York teen Jeffrey Deskovic.
Deskovic, 37, said he was introverted and aloof in high school. Classmates considered him odd and pointed to him as a suspect when the body of a 15-year-old classmate was found in 1989. At 16, he was headed to school in Peekskill, N.Y., when police intercepted him and drove him to another town for questioning without notifying his parents.
After more than seven hours of intense questioning, he falsely confessed to raping and strangling the classmate. He was convicted even though his DNA didn't match the semen collected from the victim. He was freed in 2006 after 16 years in prison and was awarded a $6.5 million settlement last month.
Police told him he failed a polygraph test -- a common tactic. During Misskelley's interrogation, when he initially professed his innocence, police told him he failed his test, though he had actually passed.
Deskovic said he believed an officer's promise that he could go home. And he assumed police would soon catch the real killer. The actual killer, Steven Cunningham, was eventually linked to the murder victim through DNA.
In one of the most high-profile cases, five teens confessed to raping and nearly beating to death a Central Park jogger. Despite a lack of physical evidence, all were jailed for more than a decade. The actual killer, Matias Reyes, ultimately confessed and was linked to the crime through DNA. While the teens were imprisoned, Reyes raped more women and killed a pregnant woman.
Richard Leo, one of the nation's top experts on false confessions, has studied what goes wrong.
"For people to say 'I'd never give a false confession' is nave," he said.
"They don't understand the situational pressures" by police trained in wearing down suspects' resistance, said Leo, a law professor at the University of San Francisco.
Tankleff said police convinced him that they had physical proof of his guilt and told him that his father briefly awoke from a coma and named him as the attacker.
The teen never considered they might lie.
Leo, who helped conduct a pioneering 1997 study of false confessions, said suspects who are young and mentally disabled, like Misskelley, are the most susceptible to police tactics.
"His case is a classic false confession in that the details didn't fit the physical evidence," Leo said.
Beth Warren is a reporter for The Commercial Appeal in Memphis, Tenn., www.commercialappeal.com/staff/beth-warren