I think this is possibly true. Although I wonder whether they present the evidence they have in a certain way such that eg
An accused starts off no comment
Is shown evidence they were the last person with victim alive - asks what they were doing.
Accused tells their version of events;
Then accused is presented with new evidence in the same interview as to next steps that evidence shows deviate from accused’s version. Does the accused then have to change their story?
I am not suggesting that the accused has not been shown all the evidence - but that it is shown in a particular way - leaving the accused either having to tell a truthful version of events, confident there will be no evidence that could come to light that would contradict this. Or, they tell one version of events but subsequent evidence comes to light that contradicts this. The immense strain on any guilty defendant then comes from having to craft a version of events that are as close to the truth as possible without knowing which bits are likely to be disproved.
It might even be the case that more footage/evidence comes to light (unlikely at this stage) even after initial charges (requests for information still being made but I wonder whether the police by now will have tracked down all vehicles that went past at that time of night to check for possible further footage and have discounted that). But equally - going full no comment all the way prior to charge until seeing all the evidence presented and not having put on record an alternative chain of events would be damaging in court (I’ve sat on 2 juries and although it is amazing how often seemingly innocuous “facts” of events can be retold or misinterpreted by different eye-witnesses, but if the accused’s version of events looks entirely tailored to the evidence presented but wasn’t volunteered then it looks damaging. Not saying all innocent people “spill” and all guilty people “no comment. Just that the order of the interview process itself can be revealing if an accused gets stuck in a version of events that cannot be true.
Investigative interviewing