>> the secret service agents thought the gunfire came from an automatic weapon fired possibly from a grassy knoll. >> i saw some police run up the -- i thought they're chasing a gunman. i ran with them. i got to the top, looked around. a policeman went over the fence so i went over the fence too. there was nothing there. >> a television newsman said he looked up just after the shot was fired and saw a rifle being withdrawn from a fifth or sixth floor window. >> it was originally thought that the shots came from in here. and now it is believed the shots came from this building here. >> the police officers are running back to the texas school book depository building. they are going to continue searching in that building for the would-be assassin of the president. >> in the federal downtown building, they are combing the area in an effort to find the suspected assassin. >> in the building on the sixth