Story highlights Mueller sent a notice, called a document preservation request, to White House staff

Request includes text messages, emails, notes, voicemails and other communications

(CNN) Special counsel Robert Mueller has asked the White House to preserve all documents relating to the June 2016 meeting at Trump Tower that Donald Trump Jr., Jared Kushner and Paul Manafort had with a Russian lawyer and others, according to a source who has seen the letter.

Mueller sent a notice, called a document preservation request, asking White House staff to save "any subjects discussed in the course of the June 2016 meeting" and also "any decisions made regarding the recent disclosures about the June 2016 meeting," according to the source, who read portions of the letter to CNN.

The letter from Mueller began: "As you are aware the Special Counsel's office is investigating the Russian government's efforts to interfere in the 2016 presidential election, including any links or coordination between the Russian government and individuals associated with the campaign of Donald Trump. Information concerning the June 2016 meeting between Donald J Trump Jr and Natalia Veselnitskaya is relevant to the investigation."

The preservation request is broad and includes text messages, emails, notes, voicemails and other communications and documentation regarding the June 2016 meeting and any related communication since then.

On Wednesday, the White House counsel's office sent a notice to White House staff informing them of the document preservation request. A second source confirmed to CNN the letter was sent to White House personnel.

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