The first detective novel was written by Christie from England. Her work, The Murder of the Oriental Express, was first published in 1897 and became a classic detective novel.
I'm not sure who exactly wrote the first Malayalam detective novel. You might need to do some research in Malayalam literary archives or consult with experts in Malayalam literature.
Edgar Allan Poe wrote the first ever detective novel. His work 'The Murders in the Rue Morgue' is considered the pioneer in the detective genre. Poe introduced elements like the brilliant detective, in this case, C. Auguste Dupin, and a complex mystery that required careful analysis to solve.
The first woman detective novel was written by Seeley Regester. Her novel 'The Dead Letter' is considered an early example in the genre with a female detective character.