The River Knows by Amanda Quick

The River Knows - Her father died and left her nothing but a library of books so she opened a bookshop. She has refused the advances of the gentleman but he did not accept her refusals and now he is dead and she must flee. She takes the little she can and fakes her own suicide.

One year later Anthony Stalbridge is investigating the affairs of Elwin Hastings because he believes Hastings had murdered his fiancée and staged it as a suicide. Mrs. Louisa Bryce is also investigating Hastings affairs, and Anthony has followed her to Hastings bedroom. As she is coming out of the bedroom a guard comes up the stairs so he catches her in a lovers embrace. Later she “hires” Anthony to open the safe in the bedroom and they agree to join forces to discover the truth behind Hastings business dealings and why he murdered Anthony’s fiancée.