But again, what evidence are you expecting there to have been? If the murderer *was* PH, he left no trace of having committed the crime, so why couldn’t another person have committed it similarly?
Where else might a perpetrator have left forensic evidence? No need to break in if the door was open (as it likely would’ve been, imo), need to be going around touching light switches in the daytime, no need to touch anything that could be used as a weapon if they’d brought their own bladed instrument, etc.
It’s very true that we don’t know everything in the case file, but if you listen to Ann’s son Ralph - a former police officer - being interviewed on
the Scottish Murders podcast (around 3m 55s) he describes being informed by the police of PH’s arrest and visiting them in Darlington to discuss the evidence that they had against PH, and how he was ‘almost sure’ that a) the evidence wouldn’t result in a conviction and that b) the police weren’t holding anything back.
Edit: sp