George Conway, White House counselor Kellyanne Conway's husband, advised congressional Democrats to subpoena "everyone and everything" related to President Trump's reelection campaign dropping the law firm that employs his former counsel Don McGahn.

The move, Conway suggested, could mean trouble for Trump if he was seeking revenge on a key witness in special counsel Robert Mueller's investigation into Russian meddling in the 2016 presidential election.

"The House Judiciary Committee should subpoena everyone and everything relating to this. Any efforts by Trump to retaliate against witnesses in the Special Counsel’s investigation would constitute additional impeachable offenses," Conway tweeted Sunday, adding, "as well as, potentially, additional criminal charges after Trump is removed from or otherwise leaves office."

... as well as, potentially, additional criminal charges after Trump is removed from or otherwise leaves office. — George Conway (@gtconway3d) April 21, 2019

The Trump campaign's decision to drop Jones Day was reported by Politico on Friday. Although campaign officials and advisers said it was a cost-saving move, Trump advisers retaliation against McGahn was also a factor.

McGahn, who served as White House counsel from 2017 until late last year, cooperated with the special counsel’s team, sitting down for several interviews. According to the Mueller team’s findings, McGahn was one of the officials who resisted Trump's orders to have Mueller fired, which might have constituted obstruction of justice.

The redacted special counsel report released Thursday showed Mueller's team examined nearly a dozen "episodes" for possible obstruction of justice. Although Mueller declined to conclude there was obstruction, the special counsel also noted that he could not say "no criminal conduct occurred."

Conway, a conservative lawyer who is a vocal critic of Trump, has repeatedly questioned the president's mental health. His tweets advising the House Judiciary Committee come after the Democrat-led panel subpoenaed for the full Mueller report, setting a deadline of May 1. The Justice Department dismissed Chairman Jerrold Nadler's subpoenas as "premature and unnecessary."