inside the halls of springfield high school, a picture of yvonne skelte. >> classmates are planning their 40th reunion. >> it is a prosecuty tight knit group. yc y yvonne daughter emily, was also on the flight. both mother and daughter have relatives still living in delaware county. at this point investigators think all 149 victims on board were murdered by the co-pilot who intentionally crashed the jetliner after locking the other pilot out of the cockpit. eight long minutes later the plane crashed into a mountain. in flights here in the united states, it's standard practice to always have two people at the front of the plane to prevent against this kind of sabotage. >> most airlines would have had a lead flight attendant go into the cockpit. >> they call yvonne and emily both amazing people. robert oliver a third american victim, was identified by the state department. >>> count on nbc 10 for continuing coverage of the deadly plane catch. for more information on the pilot's background and what we learned from those who knew him. you'll also find the latest on the crash investigation. >>