Investigators said they couldn't have solved a mysterious cold case without the help of reserve Tony Kava.

Kava volunteers with the Iowa Crimes Against Children Task Force and with the Pottawattamie County Sheriff's Department as a reserve. He is most comfortable sitting behind a computer, analyzing data and using his coding skills to solve crimes.

Investigators were looking into the November 2012 mysterious disappearance of Cari Farver. She disappeared and was never seen again, but her family and friends kept receiving bizarre texts, emails and social media posts.

"Cari was impersonated in about 12,000 emails that were sent over the years," Kava said.

In late 2016, authorities arrested Shanna Golyar for murder. They said Golyar took on Farver's identity after killing her. The motive they said was jealousy over a mutual boyfriend.

Kava said he donated around 3000 hours of work on the case, for free. Reserves are paid one dollar year. But his hard work paid off. The county created a new position in the sheriff's department of digital forensics investigator and hired Kava to do the job, KETV reports.