A few disclaimers to start:
1) I believe everyone should have the right to defend themselves.
2) Check with your local LEOs and probably an attorney for any responsibilities and legal ramifications as each locality is different.

The problem here appears to be that 911 was not promptly called and the supposed victims continued to assault the perp after he was disarmed. Not saying I think he didn't deserve it. He probably did. I am just wondering on the time frame between the initial assault and when 911 was finally contacted. I think we are all assuming it happened fairly quickly, but what if it didn't? If someone broke into your home and you disarmed them do you then have the right to hog tie and gag them and torture them for a few hours before calling the LEOs? Not much different from what might have happened to this guy. Don't gang up on me everyone, just trying to give you something else to think about. Always playing the devil's advocate, can't help myself.