VENTURA, Calif. -

A Ventura gambler who owes $500,000 to a Vegas casino has filed a lawsuit.

Mark Johnston said he should never have been given lines of credit after being served at least 20 free drinks.

He said he blacked out and doesn't remember a thing.

Nevada law prohibits allowing visibly drunk gamblers from playing.

A casino source said at one time Mark Johnston tried to do the same thing and not be responsible for his debt.

Johnston's attorney said it's routine for casinos to discount the debt of gamblers at his level.