Minor Dig on Congressional Criminal Referrals

…the DOJ generally awaits a referral from a congressional committee before investigating an alleged violation or initiating a prosecution.

In his testimony, Director Comey explained DOJ’s rationale:

We out of respect for the legislative branch being a separate branch, we do not commence investigations that focus on activities before Congress without Congress asking us to get involved. That's a long-standing practice of the Department of Justice and the FBI. So we don't watch on TV and say we ought to investigate that, Joe Smith said this – in front of the committee. It requires the committee to say, “We think we have an issue here; would you all take a look at it?”

While historical practice and comity may dictate the desirability of such a referral, the law itself does not appear to require it. Moreover, the receipt of such a referral does not require the executive branch to take action. There are several examples in which the DOJ has declined to investigate and/or prosecute in situations where congressional committees have referred potential charges to the DOJ and urged the initiation of a prosecution, particularly with regard to executive branch officials.

https://fas.org/sgp/crs/misc/crimoff.pdf