As a practical matter, they can always claim that leaking the names of the perpetrators might taint the jury pool and ruin any eventual case against them, or call it prosecutorial discretion.

Absent an actual bribe, it would be very hard to get a conviction.

Potential Legal Consequences: If it were proven that agents knowingly and willfully falsified or concealed material facts, they could theoretically face charges under 18 U.S.C. § 1001 (false statements) or for obstruction of justice. However, establishing "willful" intent is notoriously difficult, and the DOJ has currently attributed these issues to the massive scale of the review—covering millions of pages in a tight timeframe.