Now Playing: News headlines today: Oct. 3, 2018

Now Playing: Flooding, severe weather possible in Midwest, Southwest

Now Playing: Missing woman’s body found in Smoky Mountains Park

Now Playing: FDA seizes documents from Juul Labs in effort to stop teen access to e-cigarettes

Now Playing: Dozens searching for missing Maine woman

Now Playing: Masked gunman targeting Chicago neighborhood: Police

Now Playing: Chicago cop who killed black teen takes the stand

Now Playing: 4 arrested in robberies of celebrities’ homes

Now Playing: NYT reporter who broke Trump tax story details investigation

Now Playing: Ricin scare hits Trump, the Pentagon

Now Playing: The US military’s close call with China

Now Playing: FDA seizes documents from e-cigarette maker JUUL

Now Playing: Police use taser on man who stole tractor

Now Playing: Ford Motor Co. celebrates 100th anniversary of Rouge factory complex

Now Playing: Trump’s new nationwide presidential alert system being put to the test

Now Playing: FAA investigating state police use of helicopter to disperse rowdy crowd

Now Playing: Fire forces Delta flight to abort takeoff in NY

Now Playing: 4 men arrested in connection with Unite the Right rally in Charlottesville

Now Playing: Checkpoints set up in Tennessee as authorities search for suspect

Now Playing: Amazon raises hourly pay for workers to $15 after criticism