The Guardian, O'Malley Series by Dee Henderson and published by Tyndale House.
A federal judge has been murdered. There is only one witness. And someone wants her dead. U.S. Marshal Marcus O'Malley thought he knew the risks of the assignment going in ... until he fell in love. Book number two in the popular O'Malley series brings back Marcus O'Malley from The Negotiator in a tense investigative thriller. Marcus has a case to solve, an assassin to stop, and a lady to convince he's right for her future. To do that he's going to have to walk back into his own past and wrestle with the complex matter of prayer -- he's going to have to learn to trust again a sovereign God.
