Special counsel Robert Mueller’s team has asked witnesses in the Russia probe to hand over their personal phones to inspect their encrypted messaging programs.
Mr. Mueller has also requested the phones to view conversations between associates connected to President Donald Trump, said CNBC, which first reported the story.
Since April, prosecutors have been checking witnesses’ phones to examine private conversations on encryption programs WhatsApp, Confide and Signal and Dust. The witnesses have complied with the request, according to the news report.
It is unclear if Mr. Mueller discovered anything through the phone request.
The revelation comes two days after Mr. Mueller alleged in court documents that former Trump campaign chairman Paul Manafort attempted to tamper with a witness in his upcoming trial using encrypted messaging programs.
Prosecutors said Mr. Manafort and a longtime associate attempted to contact two people from The Hapsburg Group. The contacts were made via phone call, text and encrypted messages, according to court documents.
Mr. Manafort’s contact attempts were “an effort to influence testimony and otherwise conceal evidence,” prosecutors alleged in court filings. Mr. Mueller’s team asked the court to revoke or revise Mr. Manafort’s bail condition, which could send him to jail until his September trial.
Mr. Manafort has been accused of tax fraud, failing to register as a foreign agent, and lying to the FBI. He has pleaded not guilty to the charges.