Ellie Jordan: Ghost Trapper, book 2: Cold Shadows
J.L. Bryan2014

Paranormal investigator Ellie Jordan faces a difficult new case. Her new clients are a family haunted by multiple ghosts and a poltergeist that wrecks their home at night. Their seven-year-old son's invisible friends may not be imaginary at all, but the restless spirits of dead children.

To clear her clients' house of the dangerous entities, Ellie must unravel the mysterious deaths of another family who lived in the old mansion more than a hundred and sixty years ago--and she must do it before the ghosts can carry out their malevolent designs on her clients and their children.