The House Intelligence Committee is probing whether attorneys for President Trump and his family obstructed the committee's Russia investigation by shaping testimony from key witnesses, including Mr. Trump's former personal lawyer, Michael Cohen.

House Intelligence Committee Chairman Adam Schiff sent detailed document requests on March 14 to Abbe Lowell, Alan Futerfas, Alan Garten and Jay Sekulow, who represent Ivanka Trump, Donald Trump, Jr., the Trump Organization and the president himself, respectively.

"As part of its investigation of foreign influence in the U.S. political process during and since the 2016 U.S. election," Schiff wrote, the committee is "investigating efforts to obstruct authorized into these matters, including any attempt to impeded, obstruct and/or mislead the committee."

According to a letter sent in response to Schiff and Ranking Member Devin Nunes on April 5, lawyers representing those attorneys have so far dismissed the committee's requests.

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"Although the Committee has important responsibilities over this country's intelligence agencies, we are at a loss to see how that charge justifies your sweeping and unprecedented requests to our clients," they wrote to the committee. The New York Times first reported the dispute on Tuesday.

On May 3, Schiff called the group's objections "without merit" and set a since-missed deadline of May 10 for document delivery. The committee, Schiff wrote, "had a good faith basis to believe ... your clients ... may have engaged in efforts intended to obstruct authorized investigations."

"Among other things, it appears that your clients may have reviewed, shaped, and edited the false statement that Cohen submitted to the committee, including the omission of material facts," he wrote. "In addition, certain of your clients may have engaged in discussions about potential pardons in an effort to deter one or more witnesses from cooperating with authorized investigations."

A committee spokesman said the committee would be "negligent not to pursue" its leads.

"Material in the committee's possession, as well as Michael Cohen's committee testimony and admissions to the Special Counsel's Office, raise serious, unresolved concerns about the obstruction of our committee's investigation that we would be negligent not to pursue," the spokesperson said. "If any individual is allowed to lie to our committee or encourage others to do so, hide behind inapplicable privileges, or otherwise fail to provide anything less than full cooperation, other witnesses will be emboldened to similarly obstruct, both now and in the future. We must not allow that to happen."

Cohen reported to federal prison last week to begin serving a 3-year sentence for crimes including tax evasion, lying to Congress and campaign finance violations.