Jack Nicas is thrilled that the Lowell man whose innocence case he first wrote about for the New England Center for Investigative Reporting in 2010 is officially free.

Nicas, who now works a staff reporter at the Wall Street Journal, said Monday that the decision not to retry Victor Rosario by the Middlesex District Attorney’s Office is “long overdue” – coming more than three years after a Superior Court judge vacated his conviction and ordered a new trial.

The district attorney’s office filed a motion last week in Middlesex Superior Court stating that it would no longer pursue a retrial of Rosario, a former drug addict who was convicted of arson for a 1982 fire that killed eight people, including five children. More than three decades after the fire, Assistant District Attorney Thomas F. O’Reilly said many witnesses “are no longer available” and the state “cannot meet its burden” to prove Rosario is guilty.

Rosario’s story was first profiled by the New England Center for Investigative Reporting in an article published in the Boston Globe, titled, “Notorious Lowell arson case cast in doubt.’’

The story, written by Nicas, at the time a student at Boston University, and journalism professor and investigative reporter Dick Lehr, found “grave shortcomings in the police inquiry and prosecution of Rosario, findings that suggest Rosario was wrongfully convicted.”

Rosario confessed to the crime after a more than five-hour police interrogation but later claimed he was delusional at the time, likely suffering from alcohol withdrawal. Among issues, the article raised questions about techniques used in witness identification, new information about fire-scene evidence, and the possibility of a false confession.

In 2014, Nicas wrote a blog post for NECIR describing how main findings in his story were included in the judge’s grounds for a new trial. “There was excitement, disbelief and a sense of vindication,’’ he wrote. “Later, the feeling became relief. Not just that we were right, but that Victor Rosario was free.”

Lehr also welcomed the prosecution’s decision not to re-open the case. “The DA, finally doing the right thing, is welcome good news.”

Rosario, now 60 years old, became an ordained minister in prison and married his wife Beverly in 1993. He started a nonprofit called Remember Those in Captivity Ministries Inc., which aims to strengthen ties between prisoners and their families. He is an advocate for the wrongfully convicted and an avid long-distance runner, completing the New York City marathon in 2016.

Monday, Rosario said the NECIR article “brought light into darkness” of his story. He was elated to no longer worry about facing a new trial on the 1982 case. “I feel like I want to fly,’’ he said. “I feel so joyful.”

The New England Center for Investigative Reporting, a nonprofit project based out of Boston University and WGBH public radio, seeks to expose injustice by both producing and teaching in-depth, impactful journalism.

This report compiled by Jenifer McKim.