There Goes the Bride - M C Beaton

Much as it goes against the grain, Agatha Raisin is trying to be a good sport. Even though her ex-husband James Lacey's upcoming marriage to the beautiful Felicity Bross-Tilkington fills her heart with dread, she takes a break from her successful detective agency to attend the wedding. It seems like a good idea at the time--especially since Agatha's had her sights on the tres handsome Frenchman Sylvan. But as soon as she lays eyes on James, she realizes she's still desperately in love. Then, just moments before saying -I do, - Felicity is shot. And now Agatha--highly competitive, hopelessly romantic, and no stranger to scandal--is named the prime suspect for murder....

There Goes the Bride shows bestselling mystery author M.C. Beaton at the top of her game.