MOORHEAD (AP) - The father of two teenage brothers from Moorhead who died in a rollover crash in June 2015 has filed a wrongful death lawsuit.

Ray Kvalvog says the lawsuit is about finding answers, and that he'll donate any money he might win to charity.

The Interstate 94 crash near Dalton killed 18-year-old Zach Kvalvog and his 14-year-old brother, Connor, while they and two other boys were heading to a basketball camp in Wisconsin. The Minnesota State Patrol a year ago said a semitrailer was the probable cause of the crash, but the truck hasn't been found.

Kvalvog's lawsuit is against the teens' school, their basketball coach, the maker of their sons' pickup and their auto insurance provider, who all deny the claims.