Why Hawley Harvey Crippen did it has puzzled many but surely there's no puzzle in it. For the overall picture you need to read the whole of Joseph Geringer's take but this is a summary:
# Crippen was a small, serious man from
# He liked her spirit. She saw in him a way up out of her social class.
# They ended up in
# Ethel Le Neve was 18 years old when she met Hawley Crippen; at that time 39. She became his private secretary and bookkeeper and though it was romance, it was still honourable. He may have wanted it so, in contrast with his wife.
# Meanwhile Belle had redecorated her home in pink - the lampshades were pink, the vases were pink, and even the lights were pink. Crippen found her taste nauseating but learned to ignore it and went to Ethel.
# On December 6, 1906, Crippen came home earlier than usual and found one of their two lodgers in bed with Belle. He and Ethel referred ever after to December 6, 1906, as their "wedding day".
# Ethel admitted that she was pregnant.
# Belle hoped to either scare Crippen out of the house or enrage him so that he would divorce first. She used intemperate alnguage about Ethel.
# Moving to February 1, 1910 and the present tense, the story seems to be that Crippen administers a toxin to his wife and realizes he's botched the dose when Belle begins to scream. Afraid that neighbours will be roused from their beds by her screams, he panics, grabs a revolver and shoots his wife in the head.
# Now Crippen must dispose of the evidence - the only solution is dissection in his enameled bathtub. He reduces her body into parts, cutting off arms, legs and head. After filleting her, he stores the parts in the cellar and dustbin.
# At the time he would normally get up for work, he rises, dresses, shaves and heads to work, arriving at the dental office on time, as if nothing has happened.
# That evening, Tuesday, he goes straight home, eats dinner. Grabbing the sack of body parts and some bricks, he walks the few blocks to the canal and drops the package into the water.
# Crippen makes a mistake by sending a letter, ostensibly from Belle, to the Townswomen's Guild, saying she was going to
# He is interviewed by the police. He and Ethel board the S.S. Montrose as father and son, travelling to start a new life in
# Reports say: "During the day, they sat together on deck, chatting quietly about the sea and the weather. But as the voyage continued, Captain Kendall's suspicions were first aroused when he noticed Master Robinson's trousers were too large for his slender body and were held in place by means of a large safety-pin."
# Harry Kendall, the captain, had been watching the tall, slim boy and soon realized that his hips swayed unnaturally for a male and "his" hair was very soft and feminine despite the hat that covered most of it.
# Kendall makes history when on July 22 he sends the first-ever wireless telegraph that results in the capture of a criminal, from a point
# It hits the newstands in
I won't steal Geringer's thunder entirely and the last act is almost as interesting in itself but the brief of this post was to try to understand Crippen's motivation.
It seems pretty clear, psychologically. That's Ethel, below, at the trial.
[Cross-posted at Ian Appleby's Imagined Community.]