"Death In A White Tie"

"Death In A White Tie" is the 7th book in Ngaio Marsh's  Detective-Inspector Roderick Alleyn's series.  It's the height of the debutante season and even Alleyn's mother, Lady Alleyn, is attending the season.

When a woman of some standing comes to Alleyn with a story of blackmail, he enlists his good friend, "Bunchy," to help him catch a blackmailer since the ransoms are to be dropped at some of the season's biggest events which Bunchy will be attending.  What Alleyn did not foresee was murder!  When his friend Bunchy is murdered in a taxi on his way home from a late night ball, Alleyn has to set about finding out (with the help of Detective-Inspector Fox) who among the gentry might have carried out the deed that caused the death of his good friend.  After several sleepless nights of investigating, as he is falling asleep, a pattern becomes clear to Alleyn and he's ready to flush out a killer.  Another good read by Marsh!  pazt