Solving an 18-year-old murder took new science and old school persistence

In this week's "TechKnow," Crystal Dilworth visits Wasatch County, Utah, to learn more about how advances in "touch DNA" helped finally determine a suspect in an 18-year-old homicide case.

Krystal Beslanowitch was found dead December 6, 1995. Thanks to the M-Vac System, a vaccuum used to collect DNA from items someone has touched, scientists and police gathered enough DNA information from a rock used to strike Beslanowitch to identify and eventually arrest Joseph Michael Simpson.

The technological help is only part of the story. Wasatch County Sheriff Todd Bonner -- a deputy when investigation first began in 1995 -- is the reason that case stayed active enough to eventually bring in more advanced DNA collection techniques. He worked on the case even after all inital leads went cold.

Dilworth asks him why he continued to try to solve Krystal's case for so long.

"It was very, very satisfying," Bonner says of being able to call Beslonwitch's mother to share news of the arrest. "[The call is] one I will treasure for a long time."

Watch "TechKnow" for more, Sundays at 7:30PM ET/4:30PM PT on Al Jazeera America.