Taking the Heat by Brenda Novak

The small town of Florence, Arizona, is known for one thing--its prison. Gabrielle Hadley is in Florence for personal reasons, though; she's seeking the mother who abandoned her more than two decades ago. In order to support herself and her two-year-old daughter, Gabrielle is working as a prison guard--just about the only job available in this bleak desert town.
Randall Tucker is a prisoner at Florence, convicted of murdering his wife. He has one goal: to survive until he can prove his innocence--and reclaim his seven-year-old son, Landon, now living in foster care.
In the prison's atmosphere of tension and corruption, Gabrielle discovers that Randall Tucker is far from the murderer he's said to be.When he escapes during a prison transfer, she follows him into the unforgiving desert. To protect her job, her own integrity--or him? But the guard becomes the prisoner's captive...and more. It's a relationship that's not supposed to exist, and yet it might save them both.