Protection Detail by Julie Miller

Jane Boyle's life depends on her ability to keep secrets, and detective Thomas Watson doesn't realise the nurse caring for his ailing father is in the witness protection programme...or that the sparks flying between them put them all at risk.

Secret Agent Surrender by Elizabeth Heiter

DEA agent Marcos Costa is undercover and ready to bring down a drug kingpin inside his own mansion - until he runs into Brenna Hartwell, his very first love. He doesn't know she's a detective on a case and their reunion will be short-lived if their cover is blown.