Major Nidal Malik Hasan helped US soldiers face the horrors of two wars that he opposed as a Muslim - and on the eve of deploying to Afghanistan, his divided loyalties collided with horrifying consequences.

The 39-year-old military psychiatrist, recovering in a guarded hospital room from bullet wounds, remains silent on his alleged rampage at Fort Hood in which 13 people were killed and 30 wounded.

But while the motive is a mystery, a portrait is emerging of a man who spent his life healing others' mental war wounds, only to be overcome by his own demons.

Hasan's alleged journey to Thursday's bloodbath on Fort Hood base in Texas began in small town Virginia where his parents, Palestinian immigrants, ran a restaurant and were well liked members of the community.