A Ton of Gold — James R. Callan

A 178 year-old folktale causes murder, kidnapping, and arson in 2012 Texas. "A Ton of Gold" is a contemporary suspense novel, in which Crystal Moore, a young computer scientist, is dragged into danger when thugs set out to kill her 76 year-old grandmother, her only living relative. Crystal has no idea who would want to harm her grandmother, or why. But with little help from the police, she must solve this or lose the woman who raised her.
In the midst of murder, arson, and kidnapping, the man who nearly destroyed Crystal emotionally is coming back. This time, he can ruin her career.
She will need all the help she can get from a former bull rider, her street-wise housemate, and her feisty, no-nonsense grandmother.