The incident was pre archive regardless of when the article was written. What I want to know is why they weren't prosecuted for purposely obstructing an official police investigation.
No-one has been able to provide a cite detailing any illegal activity ... that is because there was none.
They weren't prosecuted for your ridiculous suggestion that they were purposely obstructing an official police investigation ... because that nonsense has no basis in fact.
As can be seen from the entirely different focus of the new investigation into Madeleine's case, the original investigators had already taken entirely the wrong route which led only to a dead end.
There would have been no conflict with the police operation; for the simple reason that the private investigators were trying to find Madeleine; the official investigators were trying to pin her disappearance on her parents; two entirely different cases.