>> reporter: the state's first several witnesses testified about basic facts leading up on to the shooting. but more central to the case attorneys on both sides argue will be that 911 call. >> so you think you're yelling help? >> yes. >> determining who is screaming for help, according to observers, could well decide the jury's verdict. >> they're going to listen to that tape over and over again to see if they can decide who was yelling for help. if they can, that may be the answer as to whether george zimmerman was a murderer. >> nbc's ron mott reporting. well, the chicago blackhawks are stanley cup champions in game six of the nhl final, brian bickell tied the score and then just 17 seconds later, the game winning shot. >> here is one thrown by frolik. they score!