Even amid mountains of evidence—eyewitness accounts, composite sketches of a suspect, or DNA left behind by a killer—sometimes, cases go unsolved, leaving already grieving families with more questions than answers and without any closure for decades.

Thanks to advancements in technology and forensics, such as the CODIS database, which allows law enforcement and laboratories to collect and share information about convicted criminals, and forensic genealogy, which uses DNA collected from a crime to trace and create a family tree for the suspect, more and more cold cases are finally being solved.

However, even with these advancements, that does not guarantee a criminal will be brought to justice, especially if they manage to evade DNA collection. Thankfully, after the killers in these cases carelessly discarded their cigarette butts, that was enough to finally crack these 10 cold cases wide open.

Related: Top 10 Mysteries And Crimes Solved By The Internet

10 Patricia Barnes

In August 1995, the body of a 61-year-old homeless woman named Patricia Barnes was found naked with two gunshot wounds to the head after her killer dumped her body in a ditch in Seattle, Washington. Despite over 100 pieces of evidence collected from the scene and a witness who provided details of a suspect to sketch artists, there were no leads in the case.

In 2018, Barnes’s case was reopened, and the evidence was sent to crime labs in Washington, Texas, and Florida that specialized in forensic genealogy in hopes of locating a relative of the killer. In 2021, one of the labs was able to locate a cousin of the suspect and later provided police with a name—Douglas Keith Krohne. Krohne was a resident of the Seattle area during the time Barnes was killed and also had a criminal history of robbery and kidnapping. However, Krohne died in 2016 during an accidental electrocution.

Once authorities had a name, they were able to cross-reference the DNA from their evidence, specifically the cigarette butts, and match it to a blood sample taken during Krohne’s autopsy, which confirmed he killed Barnes. After nearly three decades, Barnes’s family finally got closure, knowing her killer was found.^[1]

9 Paul Aikman

In 1985, 35-year-old Paul Aikman was stabbed to death at a rest stop in Oklahoma. While both fingerprints and cigarette butts were collected as evidence in the case, police were unable to identify any possible suspects.

In 2019, detectives got a break in the case…