(CNN) In the aftermath of James Comey's firing as FBI director in May 2017, Deputy Attorney General Rod Rosenstein and former FBI Deputy Director Andrew McCabe had a heated confrontation about who should recuse themselves from the Russia investigation in front of special counsel Robert Mueller, according to a source briefed on the matter.

Both men were convinced that the other was damaged by the events that had transpired and should step aside from the Russia investigation, according to multiple sources.

In the meeting with Mueller shortly after he was appointed special counsel to lead the Russia probe, Rosenstein pointed to the fact that years before, McCabe wore a campaign T-shirt in a family picture supporting his wife's bid for state senate, the source said. On the presidential campaign trail, President Donald Trump had repeatedly pointed to Democratic super PAC political donations to Jill McCabe's campaign as evidence of McCabe's political bias, and Rosenstein used the T-shirt photo as grounds for why a recusal may be necessary.

In turn, McCabe, who became the acting FBI director after Comey was ousted, was particularly disturbed by the circumstances surrounding Comey's firing and Rosenstein's role in the episode, aggressively pushing him to recuse in the days that followed, as CNN has reported

Overall, there was significant mistrust on both sides while tensions were high in May 2017, and sources suggested to CNN this suspicion colored the conversations that are now documented in contemporaneous notes McCabe handed over to Mueller.

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