Phoenix Rising by Velvet Vaughn

From the author of Be Very Quiet and Match Point comes the twenty-eighth book in the COBRA Securities Series. Phoenix Rising is an intriguing mixture of pulse-pounding suspense and sizzling passion.

Reborn from the ashes.
When a friend goes missing, FBI Supervisory Special Agent Reese Reneau enlists the help of his former team member, COBRA Securities Agent Audria Giroux, to track her down. With little to go on, they run into one dead end after another.
During the course of their investigation, feelings they both denied for years resurface, and they fall in love. Their newfound relationship is threatened when they cross the wrong person, putting their lives in danger.
As incidents pile up, Reese and Audria rush to stay a step ahead of a calculating killer. A break in the case leads to a shocking discovery . . . and an explosive climax.