(FORTUNE Magazine) – The Koch brothers' blood feud continues.

The clan of oil heirs has been fighting in court since 1982, when Bill Koch filed the first of many lawsuits against his own brothers, David and Charles, who control Koch Industries, the nation's second-largest private company. Bill has yet to win in court; his most famous lawsuit, in which he claimed his brothers cheated him when they bought his Koch Industries shares, was decided against him last month. Bill is, of course, appealing the ruling.

Bill sure is keeping busy: Next February, trial will begin in a suit filed by Bill and a business partner, alleging that Koch Industries stole oil from independent producers and cheated Indian tribes. The suit was filed under the Federal False Claims act, which means that the duo will receive up to one-third of any monies the company is forced to pay--an amount Bill says could reach $350,000. But that could be a long shot: Even the Osage Indian tribe, supposedly an aggrieved party, says it doesn't believe it was wronged by Koch Industries.

--Erin Davies