Conversation so far:
Why did Peter Sutcliffe criticize the Yorkshire police?
West Yorkshire Police were criticised by Peter Sutcliffe for being inadequately prepared for an investigation on this scale.
What was the investigation involving Peter Sutcliffe?
At Dewsbury Peter Sutcliffe was questioned in relation to the Yorkshire Ripper case as he matched many of the known physical characteristics.
Did anyone represent Peter Sutcliffe during his investigation?
Peter Sutcliffe was represented by the Attorney-General Sir Michael Havers.
What did Peter Sutcliffe do after the investigation against him?
Peter Sutcliffe was convicted several times of assault.

Question: Who did he murder?
Self-contained rewrite: Who did Peter Sutcliffe murder?