Translation of "letter of request" into French

But when they close in with more scrutiny with the letter of request

Mais quand ils étudieront la commission rogatoire, ils saisiront les comptes.

The answer at the time was to the effect that the government has taken action with respect to the original letter of request

Dans la réponse, le gouvernement affirmait avoir pris des mesures concernant la lettre rogatoire initiale