Zach Witman, who fatally stabbed his 13-year-old brother more than 20 years ago in a case that shocked and horrified the quiet bedroom community of New Freedom, was released from prison on Tuesday.

Witman, 36, was released at 9 a.m. from the State Correctional Institution at Smithfield, said Maria Finn, press secretary for the Pennsylvania Department of Corrections. He was granted parole in January.

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On Oct. 2, 1998, Witman, who was then 15, stabbed and slashed his brother, Greg, more than 100 times with a penknife, nearly decapitating him. He was a popular student at Southern Middle School and an avid soccer player.

In 2003, Witman was found guilty of first-degree murder and later sentenced to life in prison without the possibility of parole. He maintained his innocence for almost 20 years. His parents, Ron and Sue, have supported him.

MORE:Here's how Zach Witman came to plead guilty to killing brother and earn shot at parole

The U.S. Supreme Court made retroactive a ruling in 2016 that it’s unconstitutional to hand down mandatory life sentences against those who commit crimes before they turn 18. Witman was entitled to be re-sentenced.

Then, Samuel Encarnacion, Witman’s attorney, discovered that prior counsel hadn’t told his client about a proposed plea agreement. Common Pleas Judge Michael E. Bortner threw out the conviction and sentence.

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Witman decided to plead guilty to third-degree murder in exchange for a sentence of 15 years and 230 days to 40 years in prison. “Yes, I can say I killed my brother by stabbing,” he said. The statement was a stunning admission.

The murder has continued to draw intrigue. It’s been mentioned on the popular podcast “Serial.” Some people believe that mysteries still surround parts of the case.

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Ron and Sue Witman sold their home in New Freedom in November, according to York County property records. They bought a house in Lancaster County, and their son is going to move in with them.

“I couldn’t be happier,” Sue Witman said in an interview Tuesday. “I’m the happiest that I’ve been in 21 years.”

She said she believes that her son will have a decent life and be more successful than any other person in his position.

Contact Dylan Segelbaum at 717-771-2102.

Check out this photo gallery of York County's most wanted: (The photos and information published are provided by the York County Sheriff's Office. To report information on any of these individuals, call York County Crime Stoppers at 717-755-TIPS.)