Sinful Father by Andrew Allen Smith
Book two of the Masterson Files. A simple games of cards, not really. A game of cards years ago opens a series of mysterious doors to a past where General Sam Tarkington once walked the edge of right and wrong. Someone is out for revenge and it is up to Alex Brown and his team to solve a mystery and protect the elusive Jonathon Michael Masterson, but in the end, who is protecting who?