A witness says a Calgary man accused of torturing and starving his former roommate once smashed the man's head through a wall and left a huge hole.

Dustin Paxton is on trial for aggravated assault, forcible confinement and sexual assault.

The charges were laid after his former friend was dropped off at a Regina hospital in April 2010 --- battered, bruised and severely malnourished.

Lloyd Youngblut says he saw Paxton punch and kick his roommate on several occasions.

He says every day the victim seemed to have a new wound, but he took the abuse and never fought back.