this morning on world news now ambush on the border. one u.s. agent is killed, another wounded in a shooting along a very dangerous stretch in arizona. it is called cocaine alley, and drug traffickers are suspected. it s wednesday, october 3rd. announcer: from abc news, this is world news now. good morning, everybody. i m rob nelson. and i m paula faris. in a moment, the investigation into that deadly shooting of a u.s. agent in one of the most remote places along the mexican border. also this half hour, debate day in denver. if the presidential candidates are the main event, well their running mates have already provided an interesting under