Oregon Man Accidentally Killed by AR-15 He Had Just Stolen

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(Photo by George Frey/Getty Images) Local news reports

A man was killed when an AR-15 rifle he had just stolen from a Polk County farm discharged Sunday morning, police said.
Deputies responding to the report of a gunshot victim in the 5600 block of Halls Ferry Road found the suspect, 19-year-old Genaro Hernandez Mendoza of West Salem, dead inside a farm truck, said Polk County Sheriff's Office Detective John Williams.
Investigators learned that the truck had been stolen from a home on Independence Highway earlier that morning, along with a rifle, a shotgun and several other items.
"The evidence showed that while Hernandez Mendoza was driving away from the scene he was the victim of an accidental, self-inflicted gun shot wound from the rifle he had just taken." 
Williams added that the AR-15 rifle and the shotgun were both angled with their butts on the floorboard and their barrels pointed upward, toward the driver's seat. On the bumpy farm road, the bolt head of the shotgun apparently bumped against the rifle's trigger, firing one shot that hit the suspect and exited through the roof.

Do you get the impression the guns were left in the vehicle? In that case would the owner of the guns and vehicle bear any responsibility?
In other words, is it within the bounds of gun safety to leave guns in a vehicle?
What's your opinion?  Please leave a comment.