My friend James Long sent me this link: BBC NEWS | In Pictures | In pictures: Agatha Christie Comic Strip. As the BBC says, "Agatha Christie’s crime novels, already immortalised on television, on film, on stage and in audio books, have been adapted as comic strip editions." The idea is to make the books appeal to "new and younger" readers.
There’s a longer article about the project here. It seems to be a combination of cosiness and period detail that is the appeal to the publisher to use the comic book format in this case. "We like harmony and shape, and that’s what a good crime novel gives you – a lovely story arc with a beginning, middle and end – and a morally acceptable outcome, which a lot of post-modern literature will not give you. It can also give you humour, absolute horror, romance, a puzzle. Crime fiction is only going to get bigger."