Hardball with Chris Matthews 04/02/12

Is the voice yelling 'help' on 911 tape Trayvon Martin or George Zimmerman?

Forensic experts have weighed in with what they say is 99 percent accuracy: the screams on the 911 tape are not from George Zimmerman. NBC News investigative reporter Michael Isikoff, MSNBC contributor Michele Bernard, and radio host Steven Collins ... more Duration: {{video.duration.momentjs}}