The Colour of Night by David L. Lindsey
Harry Strand is a renowned international dealer in Old Master and Impressionist drawings. Working from a gallery in Texas, he is mourning the death of his wife, Romy. He is approached by the beautiful Mara Song needing to sell some precious Klimt drawings after an acrimonious divorce. They begin to form a serious friendship and she goes with him to Italy on a business trip, but one night returning to their villa they discover an intruder has left a video playing - a video showing that Romy's death in a car crash was murder not accident. Harry then reveals to Mara that before he became an art dealer he was a government agent and, disgusted by his bosses allowing a violent criminal to launder money in exchange for information, he and a few colleagues put in place their own scame to skim half a billion dollars from this man's operations and now Shrade wants it back. As Harry flees across Europe trying to outwit Shrade, he discovers that former allies are not who they seem and nor are former enemies.