LOS ANGELES, Calif.–Los Angeles police Chief Charlie Beck today ordered an internal investigation into the conviction of a man who was exonerated after spending 19 years behind bars for a 1993 gang-related killing, with the key witness saying he lied under pressure from police.

John Edward Smith, now 38, was convicted of murder and attempted murder for the drive-by shooting and, in 1994, was sentenced to life in prison. His conviction was overturned Monday and he was released last night.

“I have been briefed on the facts of this case,” Beck said. “As a result, I have directed Gerald Chaleff, our special assistant for constitutional policing and former criminal defense attorney, to form a team to thoroughly investigate the circumstances of this case.”

Beck said Chaleff and his team will report directly to him with the results of the investigation.

The Torrance-based public interest law firm Innocence Matters took the case in 2010 and contacted witness Landu Mvuemba, who immediately recanted his testimony, saying his identification of Smith in a photo lineup was the result of police pressure, Smith attorney Deirdre O’Connor said.

Cheers and applause rang out in a crowded downtown courtroom Monday as Superior Court Judge Patricia M. Schnegg granted Smith’s petition for release.

“Congratulations,” the judge told the defendant and his family, adding that the District Attorney’s Office “did the right thing” by showing no opposition.

The evidence in support of Smith’s release is “reliable” and the petition “must be granted,” Schnegg said.

Outside court, the defense attorney, surrounded by Smith’s family members, said the release was “a long time coming.”

O’Connor said Smith maintained his innocence throughout the years in prison, and always claimed he was at his grandmother’s home at the time of the shooting. She said both Smith and Mvuemba underwent repeated polygraph tests confirming Smith’s claim of innocence.

“The more I dug in, the more troubled” she became, the attorney said.

As for the original lawyers who handled Smith’s defense, as well as the initial prosecution which won the conviction, O’Connor said she “doesn’t have much good to say about anyone who handled the case early on.”

O’Connor contended in court papers that evidence about Smith’s alibi was never brought up during the trial, and prosecutors withheld statements from witnesses that pointed to another man who could have been the shooter.

In a court declaration, Mvuemba wrote that the police “laid out the whole story line telling me who did it and how,” adding that he “felt a lot of pressure to go along with it.” He claimed he tried to withdraw his identification of Smith, but still testified against him.