The public inquiry into the assassination of Daphne Caruana Galizia has entered a phase where many are both exhausted and fascinated by the testimonies, unsurprised and yet still shocked at what’s being revealed, in no doubt about the inquiry’s importance and yet wondering if it’s receiving too much importance. In short, ambivalence is setting in.

It’s on the back of this ambivalence that Robert Abela may get away with not extending the inquiry’s term beyond the end of this year.

There never was a majority strongly in favour of an inquiry to begin with. But, now, some of those grateful for the inquiry are likely to agree that enough has been heard. What are we hearing now if not confirmation of what has already been testified? What else is there to find out?

Quite a lot. To understand why, we need to distinguish between different kinds of inquiries.

For the general public, the assassination began as the kind of mystery that Hercule Poirot typically investigates: a brutal murder in a quiet country house that shakes everyone in that small world. Poirot’s central question is whodunnit.

Since we now have a general idea of who is responsible, it might seem to some that what remains are the details to be tidied up by the police to make sure the case sticks.

But asking whodunnit was never the point of the public inquiry. Its task is to find not who put the arsenic into the food but how the food was usually prepared. Did it follow health and safety rules? Were the routines careless enough to facilitate the poisoning?

This is the realm of Lt Columbo, whose central question is always howdunnit. Columbo works painstakingly through every action. If that means he needs to learn about how good wine is made, or novels written, or cosmetic products manufactured, or surgery patients sewn up, so be it. To understand the exceptional event, he needs to understand the routine.

This is the work the inquiry is doing and it’s by no means done. What comes across clearly is how Joseph Muscat and friends acted to exploit what we take to be good things in themselves, like consultation, technical committees and the civil service ethos. Fixing the Constitution alone, by limiting the powers of the Prime Minister, will not be enough.

Take the testimony of Alfred Camilleri, the top civil servant in the finance ministry. The inquiry asked whether he shirked responsibility. His justified, indignant reply was that he could not have done more.

In a functioning government, it is an irresponsible civil servant who decides to override a Cabinet decision or who second-guessed the work of the police. Had Camilleri done more than he did (treat anything that involved Mizzi with extreme caution), he would have been vehemently accused of sabotage.

And had he resigned, he would not have had a shred of evidence on which to base any accusations. All that would have happened — he claimed plausibly — is that the Electrogas consortium would have obtained what they wanted anyway, at even worse terms for Malta.

Camilleri was impeded from having full information until it was too late by the use of technical committees from which he was either excluded or else whose terms of reference were too narrow. Committees and dispersal of power — good things in themselves — were exploited to frustrate their very purpose.

Bureaucracy was used to make sure everyone, except the fixers, got a partial view. The very mechanism of transparency was used to ensure opacity.

Form was followed to poison substance. Michael Farrugia, the energy minister, told us that Muscat consulted every minister one by one when Panamagate broke out. So far, no minister has said that his advice was anything other than that Konrad Mizzi and Keith Schembri had to carry political responsibility.

It’s clear, however, that Muscat used the one-on-one form to keep his ministers from discussing matters together. He alone knew what everyone really said. He faced each minister as the boss, not as the man facing a collective Cabinet. He could study each minister’s hesitations and weaknesses and work on them personally.

He fragmented the potential internal opposition. It seems he got everyone to agree that Cabinet does not discuss “pure allegations”. When Cabinet finally did — late last year in a meeting that lasted hours — Muscat lost his hold. And he lost power.

It’s thanks to the inquiry that we know all this. Thanks to it we know that most protagonists in the howdunnit are unrepentant about the modus operandi. And if it led to disaster once, it can do so again.