Perfect Partner. New Orleans Detectives, #6

Alarm bells go off in Detective Lexi Granger's head when a gun linked to a cold case disappears and a veteran officer sweeps it under the rug. After she receives a death threat, she must turn to the one man she knows she can trust-her ex-husband and acting commander, Chaz Trahan. Chaz is still in love with Lexi but won't admit it. He agrees to help her in order to exorcise his own demons concerning the gun that is the only link to the man who killed his parents twenty years before.
But can the two of them solve the crime before the murderer finds Lexi?