Littleton School Shooting Authorities in Colorado say they are all but certain that the two high school students who carried out Tuesday's massacre at Columbine High School had help from others. Police hope security cameras in the school may provide crucial evidence. More than 900 people attended a memorial service today for 16-year-old John Tomlin, one of the students who died in the attack. In another development, President Clinton announced one-point-five-million-dollars in federal aid to help pay for funeral and medical expenses and counseling services. Noah talks to NPR's Howard Berkes who's reporting from Littleton.