Here's a little more from your link, which seems to explain that the cigar tip was not part of the leaked warrant:
"While we previously knew investigators had evidence that linked Matthew, who is also the suspect in the abduction of 18-year-old University of Virginia student Hannah Graham, to Harrington, the search warrant revelation is the first specific confirmation of that evidence.
“There was a large diffuse of stain on the shirt,” the search warrant indicated. “A DNA mixture profile was developed….on the shirt and searched against the Virginia DNA Data Bank. Search results indicated that the contributor of a foreign DNA profile, indicative of a male contributor, which was developed from a fingernail scraping of a female victim who was sexually assaulted by a male subject in a 2005 City of Fairfax, Virginia case, could not be eliminated as a contributor to the mixture profile taken from Harrington’s shirt.”
Matthew has recently been charged in connection to the 2005 sexual assault case.
Charlottesville Police then submitted a “wooden tip from a cigar butt” that Matthew had his wallet to the state crime lab.
“A DNA profile was developed from the ‘wooden tip from a cigar butt’ and could not be eliminated as a contributor to the sampling from the majority of the interior of the black t-shirt,” the search warrant continued. “The probability of randomly selecting an unrelated individual who would be included as a contributor to the DNA mixture profile is greater than one in 7.2 billion, which is approximately the world population.”
The search warrant indicated police are working with Ntelos to confirm Matthew had a working mobile phone in the Charlottesville-area the night Harrington disappeared.