Facebook’s oversight board is investigating claims the social media group allowed some high-profile users to break its rules and accused the company of withholding information on the matter.

The board, a “Supreme Court: style body created to oversee its content moderation processes, on Tuesday said it was looking into “the degree to which Facebook has been fully forthcoming” when responding to its previous inquiries about “cross-check,” an internal system used to review content from politicians, celebrities and journalists to ensure posts were not mistakenly removed.