I think Tom dropped the ball big time, as did Neri and even Michael.

Everyone was aware that Frankie was going to make peace with the Rosato Brothers. So off he goes with Willie Cicci and he never comes back. There was no body found, there is no proof he is dead, just some kind of presumption. Frankie had a wife and a family. Didnt they ask questions about what happened to him? Wouldnt they have wanted a funeral? Didn't the fact that Frankie simply disappeared raise some eyebrows? And if Frankie did disapear wouldnt Tom (or someone) have contacted "their people" with the NYPD to find out what they knew about what really happened to Cicci and Pentangeli? Did they know Cicci was alive and in some kind of witness protection program or in jail?


Also, in a rare disagreement with the estimable Turnbull, I think you are mistaken on the Statute of Limitations issue.
The Statute of Limitations on first degree murder in most jurisdictions is forever. In reality, however it would have been difficult to pin the murders on Michael so many years later (people forget things, witnesses die, etc) so they were definitely going for perjury.