The researchers found that archived latent fingerprints contained DNA; and that by using optimized methods, they could recover at least a partial DNA profile 90 percent of the time. One sample even produced a full profile. Based on their findings, the researchers believe they have exposed a new source of DNA evidence for solving future crimes as well as cold cases that have exhausted leads. Further optimization of their protocols and the use of specialized techniques for testing extremely dilute samples could expand the evidentiary value of DNA profiles from touched surfaces and archived latent prints. The study collected latent prints from volunteers in the traditional tape-and-paper technique. The prints were stored for 4 weeks. The samples were then tested for DNA. To optimize their methods, researchers used several types of powder for visualizing the prints, and they used various techniques for extracting DNA and producing profiles. Because DNA extraction from archived latent prints is destructive and removes the prints from future visual analyses, the team examined whether DNA could be recovered from surfaces where latent prints had already been lifted. They found that these surfaces do have measurable amounts of high-quality DNA, so they recommend that DNA samples be collected from the same surfaces from which fingerprints are lifted.