Kill Them All - The White Knight & Black Valentine Series, #4

They messed with the wrong supervillain. Valentina Belmonte walked away from her supervillain career years ago. Having peaked at the top of the national Most Wanted List, she now lives a quiet life with her husband and daughter, enjoying the Florida sun. Sure, she has to curb her criminal instincts to stay under the radar, but her family is worth it. Until they're attacked. With her husband-a retired superhero and the closest thing she has to a conscience-hospitalized and on the brink of death, she's done playing nice.
She doesn't know who attacked them or why, but she'll wreak bloody destruction until she finds out. Nobody does revenge like a supervillain, but as her single-minded pursuit grows more violent, it threatens the only family she has left.