Frank

Frank is the son of Big Sal.

The night Frank died Sammy was driving him.

Frank was assumed to be going to his regular card game but Frank provided Sammy with an alternate address that night.

Frank was murdered when he entered that address.

Sammy didn’t know anything but was murdered while being interogated about those events.

Sammy later finds out via Fat Phil that Tony was the one that gave that address to Frank.