MSNBC's Mika Brzezinski said President Trump "crossed another deeply disturbing line" Wednesday morning when he floated a conspiracy theory surrounding the 2001 death of one of the congressional aides who worked for her "Morning Joe" co-host and fiance, Joe Scarborough.

"Today the president crossed another deeply disturbing line," Brzezinski said in a statement obtained by New York Magazine. "With his attack on Joe this morning, the chief law enforcement officer of the United States of America advanced a false conspiracy theory to intimidate the press and cause a chilling effect on the 1st amendment."

Brzezinski said she was speaking on behalf of herself and Scarborough when she asserted the couple was "not intimidated" by the president's behavior "which contravenes both the Constitution and basic moral judgement."

Brzezinski said she and Scarborough would carry on, focusing on bigger issues such as the nuclear conflict with North Korea, with the hope that the president would do the same.

Earlier on Wednesday, Trump hearkened back to the death, 16 years ago, of Lori Klausutis, who was found dead in Scarborough's Florida district office. The president referred to it as an "unsolved mystery," an apparent reference to conspiracy theories about her death, some of which tie Scarborough into the incident. However, Scarborough was out of town at the time, according to Fox News; also, a medical examiner concluded that she fell and hit her head on a desk.

This isn't the first time Trump has gone after the MSNBC duo. The president launched personal attacks on Brzezinski and Scarborough in June on Twitter.

"Then how come low I.Q. Crazy Mika, along with Psycho Joe, came to Mar-a-Lago 3 nights in a row around New Year's Eve, and insisted on joining me," Trump tweeted. "She was bleeding badly from a face-lift. I said no!"

The two denied Trump's "flurry of falsehoods" and called said the president was "not well" in an op-ed published by the Washington Post.