A man who spent more than 18 years behind bars was freed Thursday after prosecutors vacated his murder conviction because of incorrect witness identification and shoddy work by authorities, Brooklyn District Attorney Eric Gonzalez said.

Sheldon Thomas, 35, was one of three alleged gang members charged with killing 14-year-old Anderson Bercy and wounding another person on Christmas Eve 2004 in East Flatbush, Brooklyn, prosecutors said in a statement.

“The evidence indicated that two guns were used and that the shooters were inside a white car. A witness initially identified two men she knew, who did not include defendant Thomas, as being in the car,” the statement said.

Thomas “was arrested based on a witness identification of a different person with the same name — a mistake that was first concealed and then explained away during the proceedings.”

‘It’s not just my life that was ripped apart’

In court Thursday afternoon, Thomas’ lawyers and prosecutors joined in their support for vacating the conviction.

Thomas, who wore a dark suit, thanked the judge and “the most high, heavenly father,” for guiding him throughout the ordeal.

Thomas, who was 17 when he was arrested, said he thought many times in his cell how he would respond if he were ever freed.

“I would think of this moment and replay conversations I would have with myself,” Thomas said. “Right now, I’m speechless.”

But, Thomas did, in fact, find words. He spoke about what vacating his conviction would mean to Bercy’s relatives.

“I would also like to extend my condolences to the victim’s family,” Thomas said. “I believe that since my incarceration, they have been under the impression that they were given justice for their son and come to find out today, and all this time, they really had the wrong person that was convicted for killing their son. … And it’s not just my life that was ripped apart by … the miscarriage of justice. It was them as well.”

The case won’t be retried, prosecutors said.

Investigating the conviction

The investigation into Thomas’ case was handled by the office’s Conviction Review Unit, prosecutors said.

They indicated there was poor police work because a case detective asked to unseal the defendant’s prior arrest so he could use his picture in a photo array. The prior case involved the defendant pointing an inoperable gun at officers and resisting arrest, prosecutors said.

“Before that request was completed, detectives obtained a photo of another Sheldon Thomas from a police database,” prosecutors said. “They showed an array with that photo to the witness, who identified the wrong Thomas as being in the car with 90 percent certainty. Based on her identification, the detectives went to the defendant’s address — not to the address of the Sheldon Thomas whose photo the witness had identified — and arrested him.”

Gonzalez, who was in court Thursday, said in a statement: “We must strive to ensure fairness and integrity in every case and have the courage to correct mistakes of the past.”

Prosecutors said Thomas denied any involvement in the slaying and the witness identified two different people as a perpetrator.

The incorrect identification wasn’t made known until a pre-trial hearing in June 2006.

‘It was my case, but they screwed it up’

Detective Robert Reedy, prosecutors said, initially identified the defendant as the Thomas in the photo array and testified he had never seen him before the arrest. But on cross-examination, Reedy admitted that he falsely testified, and the defendant was not in the array.

Another detective testified the defendant got on their radar based on an anonymous tip and also conceded that, when questioned a few days after the murder, the defendant had told them that it wasn’t him in the photo array, prosecutors said.

Reedy on Thursday said he led the investigation and blamed the mistake that excluded Thomas’ photo from a lineup on a subordinate detective.

He also said his department declined to pay him overtime to take part in that photo array and said that no report was written to document how Thomas’ picture wasn’t included in the initial photo lineup.

Reedy, who retired in 2007, said because of that error, he testified believing the witness selected the correct Thomas. On Thursday, he said the men with the same name look alike.

“I was the fall guy because I was the active detective,” Reedy said. “All the homicide cases I had, I handled accordingly. I never had a problem till this one because they thought about saving money. Saving money basically bit us in the ass.”

Despite Reedy’s claims about the two men with the same name looking similar, prosecutors said a study was commissioned by the defense to examine that.

Thirty-two law students of color were shown a photo of the defendant and then the photo array. Of them, 27 concluded the defendant was not in the photo array, prosecutors said. Of the other five, only one thought the Thomas in the array was the defendant, according to prosecutors.

Reedy also blamed prosecutors who initially handled the case for moving forward with it after the initial photo lineup was bungled.

Reedy on Thursday said he thought Thomas was guilty.

“If it wasn’t for the photo array, he’d still be sitting in jail — guaranteed,” Thomas said. “It was my case, but they screwed it up.”

Despite the problems, the judge found that there was probable cause to arrest Thomas based on “verified information from unknown callers” and the fact that he resembled the other Thomas from the photo array, prosecutors said.

Reedy was later disciplined following an investigation by the Internal Affairs Bureau, prosecutors said.

Other suspects

Before the trial, prosecutors dismissed the charges against one of the three suspects, who the same witness failed to identify in a lineup and because prosecutors thought he had a credible alibi, prosecutors said.

Thomas stood trial with a codefendant. The jury acquitted that codefendant. Thomas was convicted of second-degree murder, attempted murder and related counts, and was sentenced to 25 years to life in prison, prosecutors said.

The prosecution’s investigation determined because of “the erroneous photo array, there was no probable cause to make the arrest.”

The investigation also found fault in how prosecutors handled the case.

“The prosecutor also improperly elicited testimony that the witness saw the suspect whose case was later dismissed shooting from the car — without the jury knowing that the driver’s case was dismissed.”

The investigation also identified “serious errors” by the defense counsel that were detrimental and determined that judicial decisions were based on misrepresentations, prosecutors said.

The Conviction Review Unit has garnered 34 convictions being vacated since 2014. The unit has about 50 open cases, prosecutors said.