. >>> and see how volunteers like python-ron help kids with life-threatening illnesses, all coming up at 6:00. >> and ama thank you. >>> see you then, well, the ice bucket challenge has reached san francisco's top safety experts. >> that was five gallons of chilly water being dumped on the police chief. >> actually, it was way better than me. >> refreshing. >> but they deal in water all the time. we're a dry sport ball club, these guys are water people. >> the chief got his revenge moments later dumping icy water on the fire chief. all to raise money for awareness, for the disease that causes nerve cells to degenerate. also known as als. >> and he opted out of the challenge, but made a large donation to charity. >> it is cool, we did it. >> thank you for joining us. >> >>> welcome to "world news." tonight, the hunt is on for the savage killers from the terrorist group isis. dressed in black. speaking with a british accent. executing an american. and tonight, brian ross has breaking news. there was a rescue attempt that failed. >>> and scenes from severe storms. monsoon rains, and what