One Got Away by S.A. Lelchuk

Private detective Nikki Griffin is hired by Martin Johannessen because he believes his mother is being blackmailed by Dr. Geoffrey Tyler Coombs. Coombs has also gotten lots of expensive gifts (with a value of over $1.5 million) from Mrs. Johannessen, which infuriates Martin to no end. When Nikki attempts to find out more about Coombs, she finds herself attracted to him, but also drawn into a dangerous web of violence, abuse, and lies. Will Nikki be able to extricate herself safely from the situation? This second book in the Nikki Griffin series is a great read-alike for Nick Petrie, Owen Laukkanen, and Lee Child.