Killer Instincts by Anna Lee Rose
Emotionally scarred special ops veteran Jake Delgado comes home from Afghanistan only to discover that he’s been blackballed by his enemies. He becomes a hitman to support his family and is sent to Mexico to take out a notorious crime boss, but ends up falling for Hanna, his target’s captive girlfriend. She’s a beautiful, sexy woman and it’s instalove at first sight! His employer doesn’t want any loose ends and when Jake refuses to kill Hanna, they both become the target of another killer–a vicious one with ties to Jake’s own past.