Special Counsel Robert Mueller's team is asking witnesses to hand over their personal phones so they can look for conversations with anyone linked to President Trump via encrypted messaging programs, several people with knowledge of the matter told CNBC Wednesday.
The request was first made in April, and the witnesses have complied, CNBC reports. Investigators are looking at private conversations on WhatsApp, Signal, Dust, and Confide, and it's unclear what, if any, new details have been uncovered.
On Monday, prosecutors accused former Trump campaign chairman Paul Manafort of tampering with witnesses, contacting them through WhatsApp and Telegram. Manafort has been indicted for money laundering and illegally acting as a foreign agent.