Now Playing: Georgia candidate Michael Williams' campaign ad features 'deportation bus'

Now Playing: College graduate gets surprise engagement during graduation

Now Playing: Georgetown athlete walks for 1st time since suffering spinal-cord injury

Now Playing: Santa Fe gun massacre marks 22nd school shooting this year

Now Playing: Trump calls for DOJ probe, while in Texas new revelations on school shooting

Now Playing: Fresh eruptions at Hawaii volcano fuel health concerns

Now Playing: Hawaii's toxic 'laze' problem

Now Playing: Students storm high school with water guns, fireworks in fake shooting prank

Now Playing: NYPD investigates Mario Batali sexual assault claims

Now Playing: Student shot in the head describes Texas school shooting

Now Playing: Cougar kills mountain biker, injures another

Now Playing: Texas victim describes being in deadly shooting

Now Playing: High school shooter studied mass shootings: Sources

Now Playing: Father plows car into restaurant, kills daughter

Now Playing: Highlights: 'American Idol' finale, part 1

Now Playing: 'Start Here' podcast: Making sense of a shooting

Now Playing: Burglar makes sure dog stays in the house

Now Playing: Foreign exchange student killed in school shooting mourned

Now Playing: 2 families outraged after incident with service dog on flight

Now Playing: Man accused of driving his own car through his own restaurant