Facebook has been accused of misleading the European Commission over its $22 billion takeover of WhatsApp in 2014—when the Mark Zuckerberg-run company claimed that it wouldn’t be able to knit together user IDs, thereby combining the data of the two services.

Brussels’ competition officials issued a charge sheet against Facebook on Tuesday, in which it is alleged that the free content ad network failed to disclose that “the technical possibility of automatically matching Facebook users’ IDs with WhatsApp users’ IDs already existed” at the time of the merger.

Antitrust chief Margerthe Vestager said that companies must provide “accurate information” during routine competition probes into planned acquisitions.