The man behind a 1985 murder was sentenced on Thursday, nearly four years after investigators tied him to the decades-old cold case using DNA evidence taken from a used water bottle. On Thursday, a Douglas County judge sentenced 67-year-old Michael Jefferson to 32 years in prison for the murder of Roger Dean. Jefferson took a plea deal in connection with the crime, which he was arrested for in 2021 when detectives were able to match his DNA with that on evidence left at the crime scene. On Nov. 21, 1985, a man wearing a ski mask entered Dean's house in an area that is now Lone Tree and forced Dean to tie up his wife, according to a 2021 affidavit. The masked man reportedly demanded the $30,000 from the couple's savings account and got into an altercation with Dean that ended in a shooting that ultimately ended Dean's life. Witnesses said they saw the shooter running down the street of their neighborhood before getting into a car and speeding off. It took detectives more than 35 years to link Jefferson to Dean's murder and, according to the affidavit, the hair on a ski mask left at the crime scene was crucial. After advancements in technology, the Colorado Bureau of Investigation (CBI) was able to develop a DNA profile using the hair samples and entered it into a national database in 2003, but there were no hits. In 2018, detectives developed a different analysis through a separate lab, and two years later, an investigator who was well-versed in DNA genealogy identified the individuals who were likely the suspect's parents, according to the affidavit. Jefferson was one of the pair's two sons. Investigators discovered that Jefferson lived in Colorado the year Dean was killed and had a criminal history in Denver, which led law enforcement to reportedly start monitoring Jefferson. Two deputies then boarded a Spirit Airlines cross-country flight with Jefferson and retrieved a water bottle he had discarded, the affidavit said. CBI ran tests and concluded that the DNA on Jefferson's water bottle matched the profile from the samples found on the ski mask left behind in 1985, according to the affidavit. Jefferson was extradited from Los Angeles to Colorado in April 2021 on charges of first-degree murder and kidnapping. At Thursday's court hearing, Dean's daughter, Tamara, shared the impact that his death had on his wife, D.J. Another emotional testimony came from Carly Gibson, who was only 9 years old when she saw both Dean and Jefferson run from the house after the shooting. "To this day, I can recall the memory of Mr. Dean calling for help," Gibson said. "His abdomen full of bullet wounds bleeding through his shirt. Mr. Dean collapsing to the ground. Of watching Mr. Jefferson run across the snow to escape. Mrs. Dean, running out and asking for help. All of this for a 9-year-old brain to process." Retired Douglas County Sheriff Tony Spurlock also spoke on Thursday. He reminded the court that the county initially investigated Dean's wife and daughter in connection with the crime, and pointed out that the testimony of Gibson and her 7-year-old brother was dismissed. Jefferson's case is also linked to Yvonne "Missy" Woods, a former DNA analyst for the CBI who manipulated data in more than 1,000 cases. Woods analyzed the DNA in the case. The anomalies in Wood's work were part of the reasons why Jefferson ended up taking a plea deal in this case, according to his attorney. Previous reporting by Allison Sylte is included in this article.