If you will approach the question in the spirit of anglo-american legal process, then perhaps we might not speak of "perpetrators" in the case of Porto do Mós until we have some reason (other than the un-sourced accusations of later historians such as Esdaile and Oman) to think that a crime was committed. For instance, there is no mention of such a crime in the eye-witness account, only a description of a tragedy.
Your framing the question as one of "bringing to justice" the French who "perpetrated" a crime is just inflammatory and biased rhetoric at this point. A more balanced and reasoned approach might be preferred.