. >> the pope also mentioned monk thomas mertin. he was a poet and champion of nonviolence. senator cory booker there. stay with us for live coverage of the pope's events all day long on air, online, and on the go. if you're not at home or in the office, you can watch any time, anywhere. just download the nbc 4 new york app. >>> new this morning, investigators are searching for the cause of a deadly fire in brooklyn. a 10-year-old boy was killed when flames tore through his bedroom. the fire broke out just before 10:00 last night in east new york. three siblings in the room were able to escape. officials say both parents were home at the time of the fire. >>> today china's president could announce an environmental breakthrough when he meets with president obama. xi jinping was welcomed to the white house last night, and that's where he and the president will hold summit talks. xi plans to announce that china will begin a program in 2017, a cap and trade program, and that move should set pollution limits for that country. the u.s. has long pressed china to help fight global w