Lamar Johnson, a 50-year-old man who served almost 28 years of a life sentence for murder, is now walking free after a Missouri judge overturned his conviction on Tuesday. In his ruling, Circuit Judge David Mason said there had to be “reliable evidence of actual innocence — evidence so reliable that it actually passes the standard of clear and convincing.”

After he was set free, Johnson spoke to reporters in the courthouse lobby and showed gratitude to everybody who supported him in his quest to prove his innocence.

“This is unbelievable,” Johnson said according to the Associated Press.

St. Louis Circuit Attorney Kim Gardner filed a motion in August to free Johnson. Gardner’s office conducted an investigation in partnership with the Innocence Project to prove Johnson’s innocence.

“This is Valentine’s Day and this is historical,” Gardner told reporters on Tuesday.

Johnson’s attorneys condemned the state attorney general’s office for trying to keep the 50-year-old man in prison. His attorneys said the attorney general “never stopped claiming Lamar was guilty and was comfortable to have him languish and die in prison.”

“Yet, when this State’s highest law enforcement office could hide from a courtroom no more, it presented nothing to challenge the overwhelming body of evidence that the circuit attorney and Lamar Johnson had amassed,” the attorneys said in a statement.

Johnson was convicted for the murder of Marcus Boyd in October 1994. After two masked men murdered Boyd on his front porch, prosecutors said the killing happened due to a dispute over drug money.

When he was identified as a suspect, Johnson said he was spending time with his girlfriend miles away from the scene when the crime occurred. Johnson continued to defend himself at a hearing in December. Looking back at the night of the murder, Johnson said he only stepped outside the home of a friend for a few minutes on that day to sell drugs on a corner several blocks from where the crime happened.

James Howard, a 46-year-old man who’s serving a life sentence for murder and several other crimes that happened three years after Boyd was killed, also testified at the December hearing. Howard said he joined another suspect, Phil  Campbell, to rob Boyd,  who owed one of their friends money from the sale of drugs.

Howard said he shot Boyd in the back of the head and neck while Campbell shot Boyd in the side. The pair signed affidavits admitting to the crime. They also said Johnson was not involved.

Campbell, who pleaded guilty to a reduced charge in exchange for a seven-year prison term, has now died.

Witness James Gregory Elking also testified in December, saying he was on the front porch with Boyd when the crime happened. Elking said trying to buy crack cocaine when the two gunmen wearing black ski masks came around the house and began the shooting.

When police asked him to identify the gunman from a set of images, Elking said he was pressured to point to Johnson.