Missing boy 'mentally shackled by kidnapper'

For more than four years, Shawn Hornbeck seemed to have had every chance to escape, left alone for hours to ride his bike, play video games and walk past missing-child posters showing his own age-progressed image.

However, American mental health experts say this troubling case is not so simple, and that Shawn was probably kept mentally shackled by terror and domination from the man accused of kidnapping him, 41-year-old Michael Devlin.