Boiling Point by Tessa Bailey (Crossing the Line Book 3)

Con artist Austin Shaw's been in disguise so long he's not sure where his fake identities end and he begins. Now that he's been strong-armed into working for a specialized undercover unit working with the Chicago police-criminals with unique "skills"-the last thing he needs is to risk his iron control. Especially when it comes to a certain stunningly sexy hacker who tempts him with every look of disdain. Polly Banks will never, ever trust a con man. On the trail of a ruthless crook who destroyed the only family she's ever known, Polly is unnerved by the shadow who follows her every move. The one who makes her pulse pound and breath short with lust. Austin. He's infuriating, enigmatic, and pure sex appeal, and she's determined to resist him. But an untrustworthy man of disguise can become anyone he wants...including a man that Polly must trust if she's to escape their dangerous game alive.