FBI and Justice Department officials have told congressional investigators in recent days that they have not been able to verify or corroborate the substantive allegations of collusion between Russia and the Trump campaign outlined in the Trump dossier.

The FBI received the first installment of the dossier in July 2016. It received later installments as they were written at the height of the presidential campaign, which means the bureau has had more than a year to investigate the allegations in the document. The dossier was financed by the Hillary Clinton campaign and compiled by former British spy Christopher Steele.