Now Playing: Officer charged in fatal Pennsylvania amusement park shooting

Now Playing: Officer charged with voluntary manslaughter in shooting

Now Playing: 1 dead, 4 injured after shooting at Pennsylvania courthouse, officials say

Now Playing: Snow from highway overpass shatters windshield

Now Playing: 3 US troops killed, 3 wounded by roadside bomb in Afghanistan

Now Playing: Investigators find body while searching for missing 13-year-old Hania Aguilar

Now Playing: American injured during hang-gliding adventure in Switzerland

Now Playing: Kindergartners choose their morning greeting in Wisconsin

Now Playing: Video shows teacher calming pit bull after school attack

Now Playing: Deadly shooting in Pennsylvania

Now Playing: Number of cases of AFM nearly doubled in the last month: CDC

Now Playing: Massive Thanksgiving weekend storm system hammers New England

Now Playing: Cooperation deal with Paul Manafort has broken down: Prosecutors

Now Playing: GM workers respond to news of shutdown: ‘Everyone is scared’

Now Playing: 3 firefighters rescued when floor collapses during Dallas blaze

Now Playing: Active shooter scare at Walter Reed was a drill: Authorities

Now Playing: 4 high school football players charged for allegedly raping teammates with brooms

Now Playing: Active shooter drill gone awry sparks panic at Walter Reed Hospital

Now Playing: Man bitten in the head by a shark in the Bahamas

Now Playing: ‘GMA’ Hot List: What to know about the new breakthrough cancer drug