The Clocks by Agatha Christie (Warning Spoiler)

by Dave
(Washington DC, USA)

In The Clocks by Agatha Christie, I can't figure out why the murder victim was left in blind Ms. Pebmarsh's townhouse. What's the connection between her (a Commie spy) and the gentlemanly victim, Mr. Curry/Duguesclin, done in by the greedy developer next door, with help from his wife and his entreprenurial sister-in-law?

Seems like two separate plots concluded separately. Was the only link between the braille-reading red and the dead Canadian that the nasty neighbors used Pebmarsh's parlour for a body dump?