Special counsel Robert Mueller's team accused Paul Manafort of "foldering," a technique used by drug cartels and terrorist groups to secretly communicate with witnesses.

Manafort, the former chairman of President Donald Trump's campaign, was sent to jail on Friday to await trial.

Special counsel Robert Mueller's team accused Paul Manafort, President Donald Trump's former campaign chairman, of "foldering," a technique used by drug cartels and terrorist groups to secretly communicate with witnesses.

A prosecutor on Mueller's team brought up the allegation during Manafort's hearing on Friday, according to Politico. The practice of foldering is when two or more people communicate through email drafts, using an email account that all participants have the password to, rather than corresponding through sending email messages.

The technique was originally used by the terrorist group Al Qaeda and was also by David Petraeus when he tried to hide his extramarital affair during his tenure as CIA director, as journalist Yashar Ali noted.

Foldering is a communication technique that has also been used by drug cartels, according to Renato Marrioti. Marrioti said Manafort knew he was doing something wrong and did not want to be caught exchanging messages with witnesses.

Manafort was sent to jail on Friday to await trial after a federal judge revoked his bail. Prosecutors accused him of attempting to tamper with witnesses in Mueller's investigation into Russian election meddling and the Trump campaign's possible role in it.

Manafort has pleaded not guilty to over two dozen charges, including obstruction of justice, tax and bank fraud, and failure to register as a foreign agent.