To gain some clues you need to consider the following things:
Montagna made several trips to Ontario just before the killings took place, thereby strongly indicating that Montagna alligned himself with Ontario mafiosi.
Montagna visisted Nick Rizzuto shortly before he was killed and supposedly told Rizzuto that his reign was over.
After the killings it was thought that Montagna was part of the new leadership and was seeking to become the new boss.
It's stated that Montagna recently tried to muscle in on construction projects in Montreal.
Apparantly, in September there was a mob meeting in Montreal during which representatives from Hamilton and Ontario abruptly left that meeting.
In October LoPresti was killed and it was thought that he was a supporter of Montagna.
It's been stated that Tony Mucci was seen in the neighborhood where Montagna was killed in the weeks leading to the murder.
"It was between the brothers Kay -- I had nothing to do with it."
