The Haunted Lady

The arsenic in her sugar bowl was wealthy widow Eliza Fairbanks' first clue that somebody wanted her dead. The nightly plagues of bats, birds, and rats unleashed in her bedroom were the second indication, an obvious attempt to scare the life out of the delicate dowager. So instead of calling the exterminator, Eliza calls the cops, who send Hilda Adams - "Miss Pinkerton" to the folks at the bureau - to go undercover and investigate.
Hilda Adams is a nurse, not a detective - at least, not technically speaking. But then, nurses do have the opportunity to see things that the police can't, and to witness the inner workings of a household when the authorities aren't around. From the moment Adams arrives at the Fairbanks mansion, confronted by a swarm of shady and oddball relatives, many of whom seem desperate for their inheritance, it's clear that something unseemly is at work in the estate. But not even she is prepared for the web of intrigue that awaits her therein.
Reissued for the first time in over twenty years, and featuring one of Mary Roberts Rinehart's only series characters, The Haunted Lady is the thrilling follow-up to Miss Pinkerton, also available from American Mystery Classics. The books can be read in any order.