Dangerous Secrets by Chrissie Loveday

Julia Renton returns from a trip to Kenya to discover her mother is dead - evidently having committed suicide. Her brother Ryan is equally devastated and the pair rushes to their cottage in Cornwall to escape their cold and unforgiving father. Soon, a body is discovered in an outhouse and things start to go wrong, including the presumed murder of one half of an elderly pair of sisters, and the Renton's cottage burning down.
Trying to move on, Julia takes employment with Bryce Davies, a local holiday and property dealer. There seems to be something major in the pipeline and Bryce is involved, but his intentions with the Rentons are possibly less than innocent. When strange things start happening to Julia, she realises someone has made themselves involved in her life - and closer than she originally thought.