Kvalvog brothers were killed.

The parents of two brothers who died in a 2015 crash during a school trip have filed a complaint with the Minnesota Department of Public Safety alleging misconduct on the part of the state trooper who investigated the accident.

Ray and Kathie Kvalvog claim Sgt. Rod Eischens failed to disclose his close ties and friendships with administrators at their sons' school, Park Christian in Moorhead, KFGO reported.

Zach and Connor Kvalvog of Moorhead were on their way to a basketball camp in Wisconsin when their pickup crashed on I-94 near Dalton.

The Kvalvogs say Eischens' final report on the accident has many errors and should be changed to reflect that coach Josh Lee initially made false statements about the crash. The coach was in another vehicle in a caravan on its way to the camp at the time.

The official accident report determined that a semi likely forced the boys' vehicle off the interstate, but despite a nationwide search, the semi was never found.

Last year a Clay County jury found the school and Lee were not liable in a crash that killed the boys.

Minn. Dept. of Public Safety spokesman Bruce Gordon confirms that Kvalvog's complaint has been received and is under review.