There is has been some loose talk about Mueller being conflicted because Comey is his friend. Let's stipulate that a prosecutor cannot prosecute a crime where his or her friend is the victim. But this begs the question.
a. What does it mean to be a "friend" for this purpose? Do their families socialize? Or are they just former DOJ colleagues who think well of each other and perhaps have lunch now and then (they lived in different cities)? In US v. Harrelson (1985), the 5th circuit said the latter was insufficient to keep a judge from presiding in the trial of the defendant charged with killing a fellow judge. Here is how the court described the relationship between the judges. And keep in mind that the standard for recusing a judge is stricter than those for recusing a prosecutor. That is, it is harder to disqualify a prosecutor.
"Appellants were tried before Judge William S. Sessions, a federal judge of the Western District of Texas, on charges arising from the murder of John H. Wood, Jr., also a federal judge of that district. Judge Sessions had known and worked with Judge Wood for eight or nine years at the time of the latter's death and admired him. The relationship was collegial and there is no evidence of any special social relationship between the two judges or between *1165 the Wood and Sessions families. Judge Sessions was an honorary pallbearer at Judge Wood's funeral and eulogized him at several memorial ceremonies. Because of the murder, Judge Sessions was guarded 24 hours a day until December 2, 1980. The appellants contend that these facts are sufficient to render the trial court's denial of their motion for recusal reversible error."
b. What does it mean to be a "victim?" Comey was not assaulted or harmed. He lost his job but his reputation improved. A lot, I would say. He is quite marketable to BigLaw. If that's victimhood, we need a new definition of victim.
c. The question we must ask: Is there an objectively reasonable basis to anticipate that Mueller will fail to exercise proper prosecutorial discretion in order to "get even" with Trump for firing Comey? The answer is no. Any motion to recuse Mueller on these facts, even assuming a Mueller-Comey bromance which has not been shown, will lose.