The parents of two college students killed in a Tesla crash say they were trapped in the car as it burst into flames because of a design flaw that made it nearly impossible for them to open the doors, according to lawsuits filed Thursday.

The parents of Krysta Tsukahara and her friend, Jack Nelson, allege that the company that helped Elon Musk become the world's richest man knew about the flaw for years and could have moved faster to fix the problem but did not, leaving the two trapped amid flames and smoke that eventually killed them. Tesla did not reply to a request for comment.