The court official forgot to uncheck a box and the accused got hold of the witness' documents.
David Henderson had developed a reputation as a mechanic with a steady wrench and a helpful disposition, just a few clicks away on the Denver, Colorado, pages of Craigslist.
Weeks before he was murdered, Tina Black needed Henderson's help.
Black hired him and brought Henderson work on a vehicle at a hotel in August 2016. Henderson tried to remain inconspicuous in a hotel room, which swirled with guns and drugs. He discovered gloves and masks inside her car. He took photos and turned them over to police.
Henderson, 48, was heralded in court documents as a key witness to implicate Terance Black, Tina's son, in a robbery of a Denver marijuana dispensary.
It also led to his death.
Henderson was killed by gunmen two months later. A court's filing error revealed his identity to Terance Black, prosecutors said. He and an accomplice fired 10 shots that struck Henderson outside his mother's apartment. Tina Black drove the getaway car, according to Colorado's Arapahoe County District Attorney George Brauchler.
Tina Black, 51, and Terance Black, 26, were sentenced Thursday to life without parole on first-degree murder and murder conspiracy charges. Brauchler called the moment "bittersweet" - justice was served, he said Friday, but a few clicks of a computer mouse by a court official could have prevented tragedy.
"This is the nightmare scenario, where sensitive information is accidentally sent to absolutely the wrong people," he told The Washington Post. "You had a good man who was trying to do the right thing."
The fatal mistake was simple, Brauchler explained. The statewide software system default was to send criminal complaints and affidavits to all parties, including defendants and witnesses. The box was not unchecked by an official at the Arapahoe County District Court, and documents that described key details about Henderson's cooperation were obtained by Terance Black.
That error happened 1,500 times across the state in a one-year period starting last June, when the problem was raised by prosecutors, Colorado Judicial Branch spokesman Rob McCallum said. But that audit figure represented certain open cases, and the system was used for at least seven years, he said. McCallum could not say if that meant the actual number of errors was far greater.
The system now requires judges to specifically select which parties receive court files, McCallum said. In Henderson's case, it was a judge who likely made the "clerical error," he said.
McCallum declined to say if the court or state felt responsible for Henderson's death, and to his knowledge, no one has been disciplined or held accountable.
Henderson's sister Karen told reporters after the sentencing her brother was worried about retribution but still worked with police. "He didn't have the proper protection," she said, the AP reported. "It's just a shame his life got taken for trying to do the right thing."
Court records provided to The Post reveal Henderson's unexpected descent into the Blacks' criminal enterprise. Court records were sealed until Thursday to protect other witnesses, Brauchler said.
Soon after the robbery, Tina Black took Henderson to the Timber Hotel in Denver to work on a car. But there was little he could do; he needed a radiator hose from a shop that was closed.
Henderson was scared, according to an affidavit, and believed he was unknowingly drawn into a crime. He took photos of the masks and gloves and texted them to police investigators.
One unnamed witness in the hotel room connected to the incident said Terance Black pointed a gun at both of them and said not to speak about the drug operation. If they did, Black told them, "I'll kill both of y'all," the person told police.
Terance Black, after he posted bond, obtained the court records from a suspect who received it directly from the court, Brauchler said. The same witness told police Black fumed after learning of Henderson's involvement, which was "all over it . . . telling," the witness said, recounting Black's words.
Another person played a final role in Henderson's death, according to court documents.
An unnamed woman with an unclear relationship with Henderson bought crack cocaine from Terance and Tina Black in a motel the night of Henderson's murder, according to the affidavit. They asked where he was and said "snitches get stitches." The woman said she was on her way to see him. A group from the hotel room would follow her in a separate car, they told her.
She and Henderson drove around smoking crack cocaine with the vehicle on their tail. She dropped him off at his mother's apartment, where he lived. Gunshots soon rang out. She sped off.
Henderson's mother heard the shots too, court records show.
She called 911 - frantic and worried the crumpled body outside her apartment belonged to her son who just wanted to help.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)