Reporting by Paula Reid and Jeff Pegues

CBS News has confirmed that former Michael Cohen, President Trump's former personal attorney, has been collaborating with Special Counsel Robert Mueller over the past few weeks. News of Cohen's recent cooperation with the special counsel's investigation was first reported by ABC News.

Investigators have asked Cohen about any interactions between Mr. Trump and Russia, in his business dealings or during his presidential campaign. They have also asked about whether Mr. Trump has ever offered to pardon Cohen, which could be possible evidence of obstruction of justice. Cohen pleaded guilty to eight counts, including campaign finance violations, in August. Mueller's team had referred the investigation to federal prosecutors in New York earlier this year.

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Cohen's lawyer, Lanny Davis, tweeted support for Cohen, saying that his cooperation with Mueller's team showed that he was loyal to his country.

"Good for @michaelcohen212 in providing critical information to the #muellerinvestigation without a cooperation agreement. No one should question his honesty, veracity or loyalty to his #family and #country over @potus @realdonaldtrump," Davis tweeted.

Good for @michaelcohen212 in providing critical information to the #muellerinvestigation without a cooperation agreement. No one should question his honesty, veracity or loyalty to his #family and #country over @potus @realdonaldtrump — Lanny Davis (@LannyDavis) September 21, 2018

Although Cohen has not been promised leniency in his upcoming sentencing, which will be in December, his cooperation with Mueller's team of investigators may help to reduce his sentence.

Along with the guilty plea from former Trump campaign chairman Paul Manafort to charges of conspiracy earlier this month, Cohen's cooperation is a coup for the special counsel's investigation. Manafort was also found guilty on several counts of tax fraud and bank fraud in August. Mueller is now receiving information from prominent former members of Mr. Trump's circle.

Cohen told CBS News' Jeff Pegues that he was "hanging in there" in a text earlier this week.

Mr. Trump has denounced Cohen in recent months, criticizing him for "flipping" after he pleaded guilty in August.

"If anyone is looking for a good lawyer, I would strongly suggest that you don't retain the services of Michael Cohen!" Mr. Trump tweeted in August.