It's a way of sayng they haven't a case based on the info they have @Datun.
Usually, it says NFA unless further information comes to light. Which is standard.
Normally it's the Officer's Sergeant who will have taken the charging decision, based on current evidence, and often advice from CPS.
What's concerning is this letter says unless and until.
Which suggests to me that the officer is determined that it hasn't been NFA'd at all.
You can be released after interview as stil being under investigation, but this isn't it.
Bizarre and sinister. The officer is likely to have written the letter officerself.
No wonder FairCop are in a froth about it.
I wonder if the officer was on duty when it was delivered?
All these officers in Northumbria hand delivering NFA letters in the dead of night.
Or was it just this one?
What a gift to the baddies out thieving and worse.