Now Playing: First Couples' Thanksgiving Message

Now Playing: First Lady on Fight Against Obesity

Now Playing: Obama Share Thanksgiving Traditions

Now Playing: Friends, Family Stunned to Learn UNC Student Is Dead: Part 1

Now Playing: UNC Student Found Bludgeoned to Death in Her Own Apartment: Part 2

Now Playing: FBI Develops Profile of Murdered UNC Student's Killer: Part 3

Now Playing: Voicemail Found Left by UNC Student's Phone on Night of Her Murder: Part 4

Now Playing: DNA May Help Find the Identity of Who Killed Faith Hedgepeth: Part 5

Now Playing: Police Remain Confident They Will Find Faith Hedgepeth's Killer: Part 6

Now Playing: FSU Law Professor Found Shot in the Head at His Home: Part 1

Now Playing: Police Interview Murdered FSU Professor's Ex-Wife: Part 2

Now Playing: Rental Car Leads Police to Suspects in Professor's Murder: Part 3

Now Playing: Murder Suspect Linked to Family of Victim's Ex-Wife: Part 4

Now Playing: Man Claims Ex Said Her Brother Discussed Killing Her Ex-Husband: Part 5

Now Playing: Prosecutor Says Not Enough Evidence to Charge Family in Murder: Part 6

Now Playing: Elizabeth Vargas Part 1: Grappling with Anxiety

Now Playing: Elizabeth Vargas Part 2: Falling Slowly

Now Playing: Elizabeth Vargas Part 3: 'I Was So Deluded and in Denial'

Now Playing: Elizabeth Vargas Part 4: How Her Family Tried to Help Her

Now Playing: Elizabeth Vargas Part 5: Hitting Rock Bottom