I have an idea that this whole story has been drastically changed from the original Agatha Christie story because it's so totally absurd from start to finish, with a host of unbelievable characters and Miss Marple thrown into the mix for the sake of all the changes in the plotting.
WHY DIDN'T THEY ASK EVANS? never makes real sense of any plot development and why or how Miss Marple is able to deduce all that she does based on the flimsiest of clues while knitting away as though her mind is on anything but solving a murder, is the real mystery.
Again, JULIA McKENZIE does a nice job as the rather inquisitive old lady but the plot is so full of red herrings and suspicions pointed at the wrong people that it's really no fun for the mystery fan to even try deciphering the truth. The final scene is so far fetched, it has to rank as one of the most unrealistic and melodramatic endings ever shown in a Christie tale.
It appears that the writer has decided to make something very exotic out of the whole tale and whatever remains of the original is probably well hidden.