Story highlights It starts with a coerced confession

Anthony Yarbough and Sharrif Wilson go to prison over a 1992 triple murder

They are convicted for the deaths of Yarbough's mom, sister and cousin

New DNA evidence points to a different killer, also linked to a second crime

Two men behind bars for more than half their lives over a triple murder walked free this week after DNA evidence tore holes in their convictions.

Antonio Yarbough and Sharrif Wilson were teenagers when prison doors clanked shut behind them.

Now, in their late 30s, they can hardly believe they're out.

What does freedom feel like? "I'm still going through it right now," Yarbough said Friday.

"I haven't slept yet. I've been up for two days now. I have no words for it right now."

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Nearly 22 years of hard time

Imagine more than two decades in a maximum security prison. Add to that the fact that you're accused of killing your mother, your sister and your cousin.

As if that's not enough, you were the one who discovered their lifeless, bloodied bodies when you opened the door to your home one night.

If it's hard to imagine what that's like, Yarbough will tell you.

After years in Attica's maximum security prison among New York's toughest criminals, he left its high, gray walls behind him Thursday.

"It was a nightmare," Yarbough told CNN's Piers Morgan in an exclusive interview. "Twenty-one years and seven months was more like 42 years and seven months, when you know you're in prison for something you didn't do."

After reviewing DNA evidence, District Attorney Kenneth P. Thompson said the previous convictions for the 1992 murders in Brooklyn would most likely not stand up in court again and agreed the two men should be freed.

"Anybody looking at this evidence with an open mind would see that there is no chance in the world that Tony murdered his mother and these two little girls," his lawyer Zachary Margulis-Ohuma said.

And that goes beyond the DNA evidence alone. Margulis-Ohuma was convinced Yarbough was innocent years before.

At least one false confession detectives coerced out of a scared teenage boy over 20 years ago led to the convictions.

A night out

After a night of partying, Yarbough, 18 at the time, and Wilson, 15, went home to Coney Island. Wilson was staying with friends, they said.

When Yarbough got home, he opened the door to find his mother, sister and a close family friend lying stabbed and strangled to death. The two girls were partially undressed.

Police came.

"I was asked to come down to the precinct," he said. Officers said they wanted him to tell them who might have killed his family, he said.

"Before you know it, I had this photograph shoved in my face, and I was being threatened and slapped around, and they wanted me to sign a false confession. And I wouldn't," Yarbough said.

Police also took in Wilson and questioned him separately from Yarbough. But he got similar treatment, he said.

"I was scared, afraid; I was lied to, manipulated into believing that I was going to go home, if I do tell ... what they said happened." Wilson said.

Faced with a life behind bars, the young boy cooperated for the promise of lighter treatment.

Life in prison

The two were convicted in separate trials. Yarbough was sentenced to 75 years to life. Wilson got a lower sentence of nine years to life.

They sat behind bars for about 12 years, then something important arrived by mail.

"Out of the blue, I got a letter from his (Yarbough's) aunt," Wilson said. "And she asked me, did we really do it. And I had to tell the truth."

He wrote back to her: "I was wrong for turning on him, but I was scared and pressured into it." We're innocent, he told her.

"For many years I felt horrible that I had to do that and that I actually did it knowing that we weren't guilty for a crime we didn't commit," Wilson said.

"I still feel horrible now," he said, sitting next to Yarbough.

Wilson's letter led lawyer Margulis-Ohuma and the district attorney Thompson to review their cases in 2010 -- five years after he sent it.

Wrongful convictions

Thompson came into office in January with promises to restore justice to the wrongfully convicted. This case is part of a review of Brooklyn killings from the 1980s and early 1990s.

Then, last year, the right shred of evidence came along in the form of a DNA sample from a rape-murder committed in 1999.

It matched DNA found under the fingernails of Yarbough's mother, indicating that the same killer probably committed both crimes. In 1999, Yarbough and Wilson were in prison and couldn't have committed the second murder.

Margulis-Ohuma called Yarbough in prison to tell him that he was going to be free.

"When I heard about it, I was extremely overwhelmed," Yarbough said. "I was happy."

And the DNA was not the only thing that matched. The m.o. was the same, Yarbough said. The victim was stabbed and strangled.

"Hope had finally started to sink in," he said.

Free at last

Wilson and Yarbough had not seen each other for more than two decades, when they met in court Thursday.

Wilson approached the man he had testified against. "I just wanted to apologize to him for all I put him through, all I went through."

Yarbough is still in pain over it, but he faults someone other than Wilson.

"I know what they did to him, because I know what they did to me," he said.

As to finding his relatives' killer decades later, Yarbough said, "It's in God's hand's now." He teared up.

Both men celebrated freedom by fulfilling some longings they had for two decades.

Wilson filled his mouth with a hot slice of New York pizza.

Yarbough filled his lungs with New York air.