The Broncos opened a teen center in memory of cornerback Darrent Williams on Thursday, 17 months after he was shot dead in a still unsolved crime. Today’s Rocky Mountain News has a report that may jump-start the investigation, though.

The paper has obtained a letter purportedly written by Willie D. Clark, a Denver gang member who has been identified as a suspect in the killing. The letter was provided to the paper by a man who was at the Federal Detention Center in Littleton, CO at the same time as Clark, who was there on other charges.

The letter, supposedly intended for gang leader Brian Hicks, makes reference to a possible witness who “seen me with the gun and shoot out the whip.” Whip is slang for car, according to the article, which fits the description of the homicide. Clark had previously written to the paper denying his involvement in the murder and they had a handwriting expert check the two letters. “I think it’s all the same writer, period,” said Linda Collins James, a document examiner based in Plano, Texas.

After providing the letter, the source also provided other information, which the paper couldn’t corroborate, about the Williams murder and other crimes. He’s since met with prosecutors twice. They had no comment but the article cites a source as saying that they also had the handwriting analyzed and came up with a match.