Poison Flower by Thomas Perry

Jane Whitfield helps people disappear. It may be a battered wife. Or someone who found out something he shouldn't have. In Poison Flower, it's James Shelby, who was wrongly convicted of murdering his ex-wife--and who is likely to be murdered in prison to keep the real killer's identity safe. Jane helps James escape but unexpectedly finds herself being held captive by the killer's henchmen, who are desperate to know where she has stashed James. Jane has to use all of her considerable wits to escape, make sure James is safe--and make sure his sister doesn't become the next victim. All in all, it's quite the page-turner. Jane is an appealing character who is torn between her compulsion to help the helpless and her desire to have a normal life with her beloved husband, Carey. Be warned that there is a lot of violence (most of it directed toward women) in this book.