A Long Island teen was fatally stabbed at a strip mall near his high school as dozens of other students pulled out their cellphones to record the melee rather than to help him, police said. Khaseen Morris, a 16-year-old senior at Oceanside High School, was stabbed once in the chest Monday afternoon during an apparent dispute over a girl. He later died at a hospital after many of the 50 to 70 teens who gathered nearby recorded the bloody attack and made no attempt to stop it, Nassau County police said at a news conference Tuesday. “Kids stood there and...