Ermm the CPS does not conduct criminal investigations.
The link you provided is about procedure once the CPS has been given the case by LE.
You understand the difference don't you? It wasn't the CPS who went about swabbing walls and questioning people, it was LE of both countries.
Hence, CPS writing to 31 countries then a second to the Portugese. Clearly they need further assistance from Portugese LE only. Somewhere in the PJ Files is everything they need to proceed to trial.
The case exists, against someone who was in PDL at the time, by which I mean no borders were crossed by the perp. No borders other than the UK at least. They'd hardly need to send a rogatory letter to themselves.
IMO the 31 country letter was phone records, letter 2 is because of what those phone records revealed.
Letter 2 WS only sent to Portugal which tends to indicate the answers are in Portugal too - no roving gypsies, deceased Africans or Australian Yacht ladies.
The phone pings have broken this wide open :moo: