Strange that the police officer who as arrested was never charged, no explanation given……
Probably a good reason for no explanation given - if they had any sense they started to tell the investigating team everything they knew and then quietly resigned and moved far away.
On No Comment interviews - they are fine if Police have enough evidence - it lets the accused (and in particular their solicitor) know that there is enough evidence and means they should plead guilty. (Spoiler alert: That is what happens in part 3) No comment interviews only become a problem if the Police are fishing and need an admission and then any sensible person stays quiet and forces the prosecution to prove it. However, I don't know how often an explanation that they only come up with in court is ever properly challenged there - I can think of occasions when it wasn't - but that was a long long time ago. In the olden (pre-PACE) days a lot of store was set on a "Cough" and lots of dubious methods used to claim they had "coughed" - it was why PACE came into force. I know it now feels like all the advantages are given to the accused, but actually if we were accused of something - we would want that to be so. From what I can see from this type of programme the Police Interviewers are much better than in the olden days - mind you all this technology helps - being able to show CCTV film , or set out every call they have ever made is a good way of showing what they have been up to.