The Girl Beneath the Sea by Andrew Mayne

Sloan McPherson works part-time for the Lauderdale Shores Police Department as a diver looking for evidence and helping recover bodies from the local rivers and canals. As a single mom with a good relationship with her ex, Sloan is also working towards in PhD in archaeology. When she discovers a body one evening on a dive, Sloan finds herself entangled with criminals, in addition to those in authority. Teaming with ex-cop George Solar, along with help from her father and even her imprisoned Uncle Karl, Sloan tries to get the bad guys behind bars and keep herself and her daughter safe. The Girl Beneath the Sea is the first book in the Sloan McPherson series.