Special counsel Robert Mueller has amassed hundreds of thousands of records as part of his investigation into former Trump campaign chairman Paul Manafort, according to a court filing on Friday that shed new light on the scope of the ongoing federal probe.

Lawyers from Mueller’s team said they have issued 15 search warrants related to the federal investigation so far, and obtained more than “400,000 items,” including bank records, tax returns and emails. Many of the documents, which were described by prosecutors in a status report on Friday, fell into the hands of federal investigators after the FBI raided Manafort’s Virginia apartment earlier this year.