Now Playing: 'GMA' Hot List: Serena Williams on her 'fourth trimester' struggle

Now Playing: Parents of teenage boy face prison, fines for treating his seizures with marijuana

Now Playing: Man in allegedly stolen vehicle leads police on slow-moving chase

Now Playing: Worker survives van plunge off parking lot's 4th floor

Now Playing: North Korean envoy hand-delivers letter to Trump

Now Playing: Uber driver allegedly fatally shot passenger on Colorado interstate

Now Playing: 12-year-old student works in college research lab

Now Playing: Trump pardons conservative commentator Dinesh D'Souza

Now Playing: Clergy abuse survivors to receive $210 million from Catholic Minneapolis Archdiocese

Now Playing: Bodies found at kidnapping suspect's home

Now Playing: Investigators using ground radar technology at home where 3 bodies were found

Now Playing: ABC News Live: On-the-run Tennessee shooting suspect captured

Now Playing: Slain jewelry store owner's son, girlfriend charged in alleged murder-for-hire plot

Now Playing: Fugitive suspected of killing sheriff's deputy captured: Authorities

Now Playing: How Michelle O'Connell's family honors her memory for her daughter

Now Playing: Suspected cop killer caught after multiday manhunt

Now Playing: Top North Korean official to visit White House

Now Playing: Cops suspended after violent arrest caught on video

Now Playing: Friday Rewind: Deadly storms

Now Playing: How to find your sexual 'superpower'