HOUSTON --Police are investigating the death of a man after he was struck and killed by a car in southwest Houston. It happened around 2pm Thursday on the eastbound lanes of Westheimer near Dunvale in front of a Walmart. Police say a man was trying to cross the street when he was struck. The Harris County Medical Examiner's Office is investigating. Authorities closed that stretch of Westheimer, forcing drivers to turn at Dunvale and go around the scene of the accident before they could continue heading east on the roadway.