The Darkening Willows — Priscilla Dalton

It was a sad widow's task for Alice Hazard to clear out her husband's desk after his seemingly accidental death. But the emotional pang became an eerie sensation of dread and uncertainly when a mysteriously locked drawer yielded a strange, empty envelope marked: Papers Pertaining to Miss Lash.

Who was this unknown woman? Why had her name never been mentioned? And even more pressing, what had happened to the contents of the envelope?

It took the ingenuity of the clever police psychologist, Dr. Basil Wiling to solve this unusual case -- one of the most baffling murders of his career.