Michael Cohen, Donald Trump's embattled personal attorney, said Monday morning in a letter filed in a Manhattan federal court that documents seized by FBI agents last week may include information from Morgan, Lewis & Bockius and Squire Patton Boggs.

McDermott Will & Emery partner Stephen Ryan, who is representing Cohen in an investigation being led by federal prosecutors in the Southern District of New York, asked a federal judge to allow him to first review seized documents for privileged material or appoint an independent third party as special master for the review.

Ryan, Cohen and prosecutors appeared in court Monday afternoon.

Squire Patton Boggs, which a year ago this month announced a strategic alliance with Cohen, has recently sought to distance itself from the president's personal lawyer by terminating that deal and confirming that Cohen was never actually an employee of the firm. Nonetheless, the relationship between Cohen and Squire Patton Boggs continues to raise questions.

Ryan's letter on Monday left open the possibility that Squire Patton Boggs client matters referred by Cohen could have been seized by law enforcement. He claimed that Cohen referred five clients to Squire Patton Boggs and “likely participated in communications with attorneys and clients” of the firm related to these client referrals.

“We are not listing them today and defer to [Squire Patton Boggs] and its clients to assert a privilege claim,” Ryan said.

A Squire Patton Boggs spokesman said Monday that since Cohen was “never an employee or partner of our firm, and since neither our firm nor any of our clients are involved in the government's investigation, there is nothing to add to what is already stated” by prosecutors in a brief last week.

Prosecutors said last week that it is unlikely that a significant volume of attorney-client privileged material—if any—was seized in connection with Cohen's relationship with Squire Patton Boggs.

Ryan's Monday letter claimed that the documents seized by law enforcement may also include information from lawyers who advised and provided work-product to Cohen, including McDermott lawyers representing him in special counsel Robert Mueller III's investigation into alleged Russian interference in the 2016 U.S. presidential election.

Other law firms and lawyers who have advised Cohen and whose documents may be contained in the seized records, said Ryan, include Morgan Lewis tax attorney Sheri Dillon, whose work on behalf of Trump took center stage last year with regard to the president's family business and his ethical duties and obligations; David Schwartz of New York's Gerstman Schwartz Malito, Cohen's attorney in a libel suit against news website BuzzFeed; Brent Blakely, who is representing Cohen in a California suit brought by Stephanie Clifford, the porn star better known as Stormy Daniels; and Michael Sirota and David Bass of Cole Schotz, for trusts and estates and corporate advisory issues. (Cole Schotz has previously advised on Trump business matters.)

Although Cohen practiced at a few firms more than a decade ago, before he joined the Trump Organization's in-house legal team in 2006, Ryan said he does not know whether any seized records include privileged materials from those firms. Cohen worked at Estrin & Associates from 1991 to 1995 and had his own shop, Michael D. Cohen & Associates, from 1996 to 2006. Cohen also briefly worked on real estate and corporate matters at midsized New York firm Phillips Nizer, beginning in 2006.

Ryan said after Cohen left the Trump Organization in 2017, he maintained a solo practice in which he had at least 10 clients. Cohen provided strategic advice and business consulting to seven of those clients “for which privilege would not attach,” Ryan said.

For at least three other clients, Ryan said, Cohen worked on “more traditional legal tasks.”

Those clients include Trump and prominent Republican donor Elliott Broidy, who resigned on April 13 from his role as deputy finance chair of the Republican National Committee after it was revealed that he had paid $1.6 million to former Playboy model Shera Béchard after she became pregnant during an affair. (Broidy also hired Boies Schiller Flexner last month for litigation stemming from an alleged hack of his personal emails.)

A third legal client of Cohen's did not want to be publicly revealed. However, U.S. District Judge Kimba Wood ordered Ryan to reveal the identity of the mystery client, who turned out to be Fox News host Sean Hannity, a vocal supporter of Trump.

In a series of Monday afternoon tweets, Hannity claimed that he has never retained Cohen for any matter or paid him attorney fees, instead attributing their discussions to being ”almost exclusively about real estate.”

Meanwhile, the president's own lawyers from New York-based litigation boutique Spears & Imes have intervened, demanding that the U.S. attorney's office be prevented from any initial review and any documents be provided to Cohen and Trump's legal team for review.

The Spears & Imes team representing Trump in the Cohen dispute includes Joanna Hendon, a former Morgan Lewis partner who joined the firm in 2012, according to her profile on professional networking site LinkedIn.