Heartbreaking video shows one of the little girls police say was killed by her father, Chris Watts, last week.
Watts, 33, allegedly admitted Wednesday to killing his wife, 34-year-old Shanann, and daughters, Bella, 4, and Celeste, 3. Watts’ wife was 15 weeks pregnant at the time.
"My daddy is a hero," Bella sings in the newly surfaced video. "He helps me grow up strong."
In another video from six years ago, Watts can be seen practicing a presentation for a college course in which he talks about relationships.
"Sometimes you no longer find your partner attractive physically or in their personality," he says. "When somebody is not faithful to their partner, the partner realizes the relationship cannot be sustained."
Shanann's co-worker, Nickole Atkinson, is believed to be the last person to see Shanann alive. She told "Good Morning America" she was not shocked by Watts' arrest.
However, Atkinson said Shanann appeared to be in a happy marriage.
"No, she did not talk about leaving him or separating. She very much loved her family and wanted to be a family,” Atkinson said. "I didn't find out that they were going to separate or anything like that until I called Chris that morning."
But other friends said Shanann had feared her husband was being unfaithful.
"It came to her mind that possibly he could be cheating," Amanda Thayer told CBS News last week.
Watts is being held in Weld County Jail, where he was booked on three counts of first-degree murder and three counts of tampering with physical evidence. He has not yet entered a plea.