What's Left Behind by Gail Bowen

Joanne's son Peter's wedding is overshadowed by the appearance of the maid of honor Lee's ex-boyfriend, Simon. Simon is still obsessed with Lee and has checked himself out of the psychiatric hospital against his doctor's orders.  Lee, with her organization Citizens for Planned Growth has been fighting against corporations that want to take over farmland and are more concerned with making money than responsible development. When Lee is found murdered soon after the wedding, the authorities' prime suspect is Simon, but Joanne and others believe that Lee's work with her group or possibly personal relationships in her past will be the key to finding her killer.  As usual in this long-running series, the reader is contentedly immersed in Joanne's world of family, friendships, and politics.