LINCOLN, Neb.—The parents of a couple who died with their children in a fiery chain-reaction accident in western Nebraska have filed a wrongful death lawsuit faulting three truck drivers and the transportation companies that employed them.

One of the drivers died in the September accident and another is facing manslaughter charges. The lawsuit alleges that truck driver, Josef Slezak, had been on the road for too long.

The lawsuit was filed late Monday in U.S. District Court of Nebraska by the parents of Christopher and Diana Schmidt, a Gaithersburg, Md., couple who were killed along with their two young children and unborn son.

Read the tragic story here.