Now Playing: FBI investigates deadly building explosion

Now Playing: At least 1 killed, 3 injured after explosion rocks medical building

Now Playing: Students say Illinois school shooting suspect made threat on Snapchat

Now Playing: Ohio teacher to donate kidney to 10-year-old girl

Now Playing: Nassar blames victims in police videos

Now Playing: The volcano 'Code Red' in Hawaii

Now Playing: Deadly explosion at California day spa wasn't an accident, officials say

Now Playing: Officer shoots armed former student at Illinois high school

Now Playing: Amber Alert issued after Florida girl forced into SUV

Now Playing: Fiery crash caught on traffic camera

Now Playing: Wife of PGA Tour pro arrested on domestic violence charges

Now Playing: Senate votes to undo FCC net neutrality repeal

Now Playing: Family of five remember late mother who struggled with postpartum depression

Now Playing: 'GMA' Hot List: The 'laurel' vs. 'yanny' debate divides the nation

Now Playing: Suspected drug smuggling ring busted at DFW

Now Playing: A sweet job for doughnut lovers

Now Playing: Texas family targeted in 'swatting' prank

Now Playing: 'The View' honors veteran who served in Vietnam

Now Playing: 6-year-old with epilepsy gets a surprise visit from NBA all-star

Now Playing: 'Heroic' officer hailed for stopping armed teen at high school, saving lives