Karen Setian and Inaida Nalbandian have filed a lawsuit against Lane -- who's currently serving 40 months in prison -- for the wrongful death of their 17-year-old son, Vahagn Setian.
Karen and Inaida claim Lane "purchased a bottle of vodka with and for minors, brought the vodka to a party attended by minors ... and shared and consumed the vodka with minors at the party."
The parents claim that's when Lane loaded up his car with three high-schoolers and headed to a Beverly Hills liquor store -- the trip was fatally interrupted when Lane crashed into a tree.
The suit, which we just found, was filed last month. The parents are seeking unspecified damages.