Now Playing: Possible Serial Killer on the Loose in Virginia

Now Playing: Michelle Obama Speaks to Virginia Tech Graduates

Now Playing: Woman allegedly paid dark web company in bitcoin to kill lover's wife: Prosecutors

Now Playing: 'She's a very calming person:' Mother-in-law of Southwest hero pilot

Now Playing: SAP pledges to plant 5 million trees by 2025 on 'GMA'

Now Playing: Men arrested at Starbucks speak out

Now Playing: Pro surfer saves lives amid torrential Hawaii rain

Now Playing: David Copperfield reveals illusion under oath

Now Playing: Puerto Rico hit by massive power outage

Now Playing: Deadly fires tear across the Southwest

Now Playing: Trump says he may leave meeting with Kim Jong Un

Now Playing: New inspections ordered on planes after deadly engine failure

Now Playing: The VR therapy designed to help sexual assault survivors heal by facing attackers

Now Playing: Torrential rains spark flash-flood watches throughout Hawaii

Now Playing: Pilot who handled Southwest emergency landing hailed as 'true American hero'

Now Playing: Former first lady Barbara Bush, in her own words

Now Playing: David Copperfield forced to reveal some of the magic behind tricks

Now Playing: Former President George W. Bush speaks on the passing of his mother

Now Playing: Oklahoma scorched by dangerous wildfires fueled by droughts, winds

Now Playing: Passenger killed in Southwest engine failure remembered as family's 'bedrock'