PHOTO: Pepper Hamilton LLP
Now playing
01:24
Man freed after 21 years for murder he didn't commit
Now playing
01:33
Chuck Schumer announces timeline for Trump impeachment
Registered nurse Irene Musni administers the COVID-19 vaccine into the arm of a senior citizen at the Corona High School gymnasium in the Riverside County city of Corona, California on January 15, 2021, a day after California began offering the coronavirus vaccine to residents 65 and older. - US President-elect Joe Biden was set to announce his Covid-19 vaccine rollout plan Friday as he bids to wrest the focus from the impeachment of Donald Trump to the agenda for his first days in office.
Biden has said he wants 100 million Americans to receive shots during his first 100 days in office, an ambitious goal that would require a big step up in the current pace of distribution. (Photo by Frederic J. BROWN / AFP) (Photo by FREDERIC J. BROWN/AFP via Getty Images)
Registered nurse Irene Musni administers the COVID-19 vaccine into the arm of a senior citizen at the Corona High School gymnasium in the Riverside County city of Corona, California on January 15, 2021, a day after California began offering the coronavirus vaccine to residents 65 and older. - US President-elect Joe Biden was set to announce his Covid-19 vaccine rollout plan Friday as he bids to wrest the focus from the impeachment of Donald Trump to the agenda for his first days in office. Biden has said he wants 100 million Americans to receive shots during his first 100 days in office, an ambitious goal that would require a big step up in the current pace of distribution. (Photo by Frederic J. BROWN / AFP) (Photo by FREDERIC J. BROWN/AFP via Getty Images)
PHOTO: Frederic J. Brown/AFP/Getty Images
Now playing
01:55
Race to vaccinate before more contagious Covid-19 strains spread
WASHINGTON, DC - JANUARY 22: U.S. President Joe Biden signs an executive order as Vice President Kamala Harris looks on during an event on economic crisis in the State Dining Room of the White House January 22, 2021 in Washington, DC. President Biden spoke on his administration
WASHINGTON, DC - JANUARY 22: U.S. President Joe Biden signs an executive order as Vice President Kamala Harris looks on during an event on economic crisis in the State Dining Room of the White House January 22, 2021 in Washington, DC. President Biden spoke on his administration's response to the economic crisis that caused by the COVID-19 pandemic and signed two executive orders. (Photo by Alex Wong/Getty Images)
PHOTO: Alex Wong/Getty Images North America/Getty Images
Now playing
02:31
Biden zeroes in on the teetering economy in first week
A group of protesters shield themselves from chemical irritants as they demonstrate Wednesday evening, Jan. 20, 2021, outside the U.S. Immigrations and Customs Enforcement (ICE) building in Portland, Ore. (Assfault Pirates via AP)
A group of protesters shield themselves from chemical irritants as they demonstrate Wednesday evening, Jan. 20, 2021, outside the U.S. Immigrations and Customs Enforcement (ICE) building in Portland, Ore. (Assfault Pirates via AP)
PHOTO: Paul L/AP
Now playing
04:04
Portland protesters explain why they are taking to the streets
Hank Aaron, Milwaukee Braves
Hank Aaron, Milwaukee Braves' outfielder, is shown in a posed batting portrait at the Polo Grounds, Brooklyn, during the exhibition season, 1954. (AP Photo)
PHOTO: AP
Now playing
02:30
Hank Aaron, baseball legend and former home run king, dies at 86
PHOTO: CNN
Now playing
01:23
Schumer says articles of impeachment will be delivered Monday
US President Joe Biden listens to the US National Anthem during the virtual Presidential Inaugural Prayer Service hosted by the Washington National Cathedral, in the State Dining Room of the White House in Washington, DC, on January 21, 2021. (Photo by MANDEL NGAN / AFP) (Photo by MANDEL NGAN/AFP via Getty Images)
US President Joe Biden listens to the US National Anthem during the virtual Presidential Inaugural Prayer Service hosted by the Washington National Cathedral, in the State Dining Room of the White House in Washington, DC, on January 21, 2021. (Photo by MANDEL NGAN / AFP) (Photo by MANDEL NGAN/AFP via Getty Images)
PHOTO: Mandel Ngan/AFP/Getty Images
Now playing
03:02
Biden unveils Covid-19 plan on first full day in office
Now playing
00:00
Dr. Fauci vows to be 'completely transparent' on Covid-19
Iraqi security forces keep guard the site of a suicide attack in Baghdad, Iraq January 21, 2021. REUTERS/Thaier al-Sudani
Iraqi security forces keep guard the site of a suicide attack in Baghdad, Iraq January 21, 2021. REUTERS/Thaier al-Sudani
PHOTO: Thaier al-Sudani/Reuters
Now playing
02:42
Dozens killed and hundreds injured in Baghdad suicide blasts
PHOTO: CNN
Now playing
05:46
Dr. Gupta on Covid-19: This is the worst it's ever been
Now playing
03:04
Avlon: QAnon supporters left desperate and disillusioned
Now playing
03:17
Many believed conspiracy theories about Trump and the election. Now, they're losing faith
PHOTO: Courtesy Owen Harrington
Now playing
04:22
He bonded with Biden over stutter. Then got call to speak at inauguration
US President Joe Biden swears in presidential appointees during a virtual ceremony in the Oval Office of the White House in Washington, DC, after being sworn in at the US Capitol on January 20, 2021. (Photo by JIM WATSON / AFP) (Photo by JIM WATSON/AFP via Getty Images)
US President Joe Biden swears in presidential appointees during a virtual ceremony in the Oval Office of the White House in Washington, DC, after being sworn in at the US Capitol on January 20, 2021. (Photo by JIM WATSON / AFP) (Photo by JIM WATSON/AFP via Getty Images)
PHOTO: JIM WATSON/AFP via Getty Images
Now playing
01:29
'I'll fire you on the spot': Biden tells staff to treat others with respect
President Joe Biden signs his first executive order in the Oval Office of the White House on Wednesday, Jan. 20, 2021, in Washington. (AP Photo/Evan Vucci)
President Joe Biden signs his first executive order in the Oval Office of the White House on Wednesday, Jan. 20, 2021, in Washington. (AP Photo/Evan Vucci)
PHOTO: Evan Vucci/AP
Now playing
02:56
Biden signs executive actions aimed at dismantling Trump's policies
Harris
Harris
PHOTO: Senate Tv
Now playing
02:01
A proud Harris smiles as she swears in new senators in her new role
(CNN) —  

A Pennsylvania man who spent 21 years behind bars for murder was freed Wednesday after the star witness in the case confessed to the killing.

John Miller walked out of the State Correctional institution in Frackville, about 100 miles northwest of Philadelphia, after prosecutors declined to retry him, saying there was insufficient evidence, according to court records.

“I’m very happy and excited that after 21 years I’m finally being heard and that my innocence has reached the surface,” Miller said in a written statement distributed by his attorney. “I’m going home to my family. I’m overwhelmed, excited, and happy.”

Miller, 44, credited his attorneys with securing his release after years of declaring his innocence.

John Miller has always maintained his innocence.
John Miller has always maintained his innocence.
PHOTO: Pepper Hamilton LLP

“Without them, I don’t know what would have happened or where I would have been,” he said.

Miller was convicted in 1997 for the October 1996 murder of Anthony Mullen during a robbery attempt outside the 30th Street Station, Philadelphia’s main railroad station, according to court records. Mullen had been shot to death. A jury convicted Miller of second-degree murder, and he was sentenced to life in prison.

David Williams was the witness who identified Miller as the killer, according to court records. Williams told police in exchange for leniency in another case that Miller had confessed to him that he killed Mullen, the court records show.

’I can’t live with this on my conscience’

But Williams recanted his statement even before Miller’s preliminary hearing, and “he has been confessing to Mullen’s murder for more than a decade,” the Philadelphia District Attorney’s Office wrote in a motion filed Monday that declined to retry Miller.

Williams even sent a letter to Miller’s mother in December 2002, saying in it that he committed the murder.

“I can’t live with this on my conscience. Your son had no knowledge of this crime. He wasn’t even there. I lied on him,” he wrote, according to court records.

Miller filed 10 appeals, his attorney, Thomas Gallagher said. All were denied, he said.

Miller’s legal team, which included the Pennsylvania Innocence Project, took on the case eight years ago and found evidence that had not been previously disclosed to Miller’s defense team, Gallagher said in a news release. That evidence raised questions about what authorities knew about Williams initial testimony, according to court records.

A federal judge on July 1 ordered Miller be released, subject to a decision by the district attorney on whether to pursue a new trial.

’Insufficient evidence’ to make a case

In a motion filed this week, the District Attorney’s Office said there was “insufficient evidence” to make a case against Miller.

“Williams’ statement to the police was the crux of the case against defendant,” the motion said.

On Wednesday, a Common Pleas Court judge agreed and ordered Miller released.

CNN was unable to reach Williams for comment, and it was not immediately known if he had an attorney. The District Attorney’s Office has not said whether it will charge Williams in the Mullens murder.