A Fort Hood soldier from Tyngsboro said yesterday he’s stunned the man suspected of turning the Texas base into a killing zone, murdering 13 and wounding 28, is a psychiatrist entrusted to help GIs.

“The biggest shock was finding out his rank and what he did for the Army,” said Sgt. Timothy Dunbar, 28, who works for command staff at the base. “I was just completely lost for words.”