Law enforcement sources tell TMZ ... Andrew Stern shot himself in the head Sunday while he was at a shooting range in the San Fernando Valley.
The 40-year-old businessman was married to Katie ... who was also a contestant on "America's Next Top Model." Katie was photographed in Cannes last month with Leo and the two seemed tight.
There are also photos of Katie in Cannes with "Entourage" star Adrian Grenier." TMZ reports. Continue...