That would be the older way of doing things, but just from my observations of policing these days, it seems investigators never reveal who is under suspicion and who is not. IMO they don't want killers at large to know anything about who they suspect, it's a strategy of never announcing what cards you have in your hand.Idsinga knows the tremendous amount of speculation out there in the public relating to the possible involvement of at least one family member in particular in these murders. This speculation has been fueled and accelerated by media reports, and by KD's book, which outlines what some would term negative interactions between family members and Barry and Honey. Knowing this, and the tremendous amount of hurt that these rumours must be causing the family, why do you think Idsinga didn't simply state something like "at this time we have no evidence to link any members of the Sherman family to the murders"? Wouldn't this have been a direct way to deal with the issue, instead of obfuscating, and thereby allowing these rumours to persist, to the detriment of the family?
We saw yesterday, how a guy who was never a suspect, committed the Christine Jessop murder. IMO, until someone is (rightfully) convicted, police can never officially state that anyone is 'cleared'.
And I think part of the strategy of the media is to try to goad LE into making statements like that, it produces front page stories. Whereas, IMO, police aren't and don't want to turn into puppets of the media circus, as they sometimes seem to be in the US.