Cached Out — Russell Atkinson

Newly retired from the FBI and alone after the tragic death of his wife, Cliff Knowles takes up geocaching. While looking for a cache in the mountains he comes across a human skeleton and reports it to the sheriff's office. Then a second body is found - a fresh corpse this time - right after Cliff found another geocache nearby. When it turns out the first remains are those of a fugitive he was supposed to arrest years earlier, he becomes a suspect in a multiple homicide investigation. He has no choice but to use his sleuthing skills to identify the mysterious cache owner, known only as Enigmal, and free himself from suspicion.