... this short story compilation from the British Library Crime Classics series looks like it would fit the bill.  (Link to Obi's review in the header and here.)

Note: For those looking for a print edition, I've also added the paperback edition to this post.

A grumpy, old woman who was hated by everyone and died with five blows on the back of the head

A professional assassin, a mafia family, the FBI and the NYPD… mix them up in intelligence and counter-intelligence, you get a page-turner of a novel.

Ordeal By Innocence, the 1958 novel of Agatha Christie, is the first book I’ve read among Christie’s long list of novels.

Detective William Monk wakes up in a hospital and suffers from amnesia after meeting an accident. At the same time, he is in a middle of a crime investigation. He tries to piece his past and the crimes almost simultaneously until he remembers an event that would possibly put him as a murder suspect