Two separate inquiries have now been announced following the BBC Spotlight allegations against the Robinsons, with further moves possible.
But it seems likely that any such proceedings will have limited remits, each leaving some aspects of the overall case untouched. That creates the risk that the controversy will not be satisfactorily resolved.
The First Minister yesterday announced plans to appoint a lawyer to examine whether he has breached the Ministerial Code.
This has to be a special appointment because Stormont has yet to establish an independent procedure for adjudicating on alleged Ministerial Code breaches.
Up to now, the only way to bring a complaint was through a High Court case.
Assurances will inevitably be sought on the independence of the lawyer in charge of this review.
His remit may simply involve establishing if Mr Robinson was obliged to report his wife for not making register of interest declarations on funds received from two developers.
The Ministerial Code requires Ministers to act in the public interest at all times.
It seems likely that the review will effectively be a judgement call by the lawyer.
There is a more general question as to why Mrs Robinson did not make belated declarations, after her husband learned about the money.
It is not yet clear if this question will be covered in the review announced by Mr Robinson.
Castlereagh Council has announced an investigation of its own, following the Spotlight programme.
Meanwhile, the Code of Conduct for MLAs - not to be confused with the separate Ministerial Code - may well come into play as well.
That would require a standards complaint to be made, which would be investigated by the Stormont Standards Commissioner. The final verdict on such a probe would rest with MLAs on the Standards Committee, which has voted along party political lines in past cases.