PROVIDENCE — An organization dedicated to exonerating wrongly convicted people is intervening in the appeal of a Cranston man serving two life terms for shooting a man to death as he sat in an SUV on a Providence street.

The state Supreme Court gave the New England Innocence Project the go-ahead to file a brief in support of Tracey Barros’ appeal of his 2008 murder conviction. Barros, 30, is serving double life terms, plus 10 years, for killing 26-year-old Deivy Felipe as Felipe sat, unarmed, in a car on Althea Street four years ago.

The public defender’s office has appealed that sentence to the high court. Among the things his lawyers are questioning is why the police recorded only 12 minutes of their four-hour interview with Barros, Assistant Public Defender Michael A. DiLauro said. Though Barros confessed to the crime in the recording, he has since denied responsibility, insisting he was coerced into making the statements.

“Some of the things he said were inconsistent with the physical evidence,” such as the number of shell casings and the angle at which Felipe was shot, DiLauro said. No physical evidence directly links him to the crime, he said.

The New England Innocence Project is asking the court to use the case to send the police a message that interviews with suspects in custody should be recorded as proof that a confession was given voluntarily. False confessions are one of the leading causes of wrongful convictions, and DNA evidence has proven they do occur, according to Andrew Horwitz, a professor at the Roger Williams University School of Law.

“Where is everything that led up to [the 12 minutes]?” said Horwitz, who works with the Innocence Project. The organization, a leg of the national branch, provides pro-bono legal services to clear people who were wrongly convicted through the use of DNA and by probing the roots of false convictions. Barros’ first trial ended in a hung jury.

But state prosecutors argue that the confession, gathered by the Providence police and an agent of the Bureau of Alcohol, Tobacco, Firearms and Explosives, is legitimate.

“I submit to you that if this defendant’s interview was recorded in its entirety, upon playback it would reiterate exactly what he admitted in his partially recorded interview — that Tracey Barros murdered Deivy Felipe,” said Michael J. Healey, spokesman for the attorney general’s office. “He voluntarily admitted his guilt. Nobody coerced him.”

Officers found Felipe slumped dead at the wheel in April 2005 in what the police described as a drug deal gone bad. He had been shot five times. Barros was arrested eight months later by officers patrolling South Providence after they saw him run into a house with a gun. According to the police, Barros told them at the station that Tonea “Nutt” Sims gave him the handgun that he used to shoot a man in an SUV whom he did not know because he owed money to Sims.

A fledgling filmmaker, Sims — whom a witness described as the “baddest and worst person in the city of Providence” — wrote, directed and starred in a homemade movie that captured the underbelly of Providence’s drug world. Sims, 34, was shot to death earlier on the day of Barros’ arrest.

The Innocence Project’s effort is part of a national push to mandate that police record all interviews of suspects in custody. Legislation to require recording has been proposed in Rhode Island several times, but has failed to win approval.

Eighteen states, including Massachusetts, have backed recording, either through legislation or judicial action, DiLauro said.

In Rhode Island, U.S. District Judge William E. Smith has twice instructed juries to view with caution police testimony about interviews that have not been recorded. He said the instruction was intended to prod agencies to change their policies and record the interrogations of people in custody. The Rhode Island Police Chiefs Association opposes any law mandating recording.

The Innocence Project takes on cases in which DNA evidence is in question, questionable confessions are at play, or the science is unreliable, said David M. Siegel, who sits on the New England Innocence Project’s board and is working on the Barros case.

In 2005, the organization was involved in seeking DNA tests that a defense lawyer argued could clear Raymond D. “Beaver” Tempest Jr. in the high-profile bludgeoning death of Doreen C. Picard of Woonsocket. Those results are still coming in from the lab, but no further action has been taken in the case, Healey said.

kmulvane@projo.com