June 15, 2006 — -- After billionaire Howard Hughes died in 1976, a gas station owner, Melvin Dummar, claimed Hughes had left him $156 million in a handwritten will. But he's never seen any of that money.
Nearly 30 years later, 61-year-old Dummar is back in court this week, claiming he was cheated out of his inheritance and that Hughes' estate hid evidence from him. Dummar's new lawsuit does not contend that the alleged will was authentic. Instead, the suit argues that two of the major figures in the Hughes estate -- Frank Gay and William Lummis -- used fraud to prevent Dummar's claims from getting a fair hearing.
The lawsuit implies that some witnesses in the case were bribed to change their testimony.
"I tried to treat other people with respect and dignity," Dummar says. "And for the last 30 years, that's all I really wanted for myself, for my family."
Dummar says he was willed the money for saving the billionaire's life, when he found Hughes dazed and alone in the Nevada desert. A Las Vegas jury ruled against him, and he was labeled a fraud by newspapers across the country. An Oscar-winning movie, "Melvin and Howard," depicted the story.
Now, as a new witness, Robert Deiro, Hughes' former pilot, steps forward, there's a chance that Dummar could get some of what he believes he's due.
"I think Melvin Dummar was diddled," Deiro says.
Dummar, who worked at a gas station in Utah at the time of the original incident, claimed that while driving on a desert road in rural Nevada in late 1967, he pulled over to help a disheveled old man. That man claimed to be Howard Hughes, one of the richest men in the world.
He says he never believed it was really Hughes but agreed to drive the old man to Las Vegas as requested and even lent him a quarter before saying goodbye. A few years later -- after Hughes' death -- Dummar says a handwritten will was delivered to him, purporting to leave him one-sixteenth of Hughes' massive fortune.
Dummar claims he is pursuing the case not for the money but to clear his name.
"No, it's not just about the money," he says. "It's more to do with the truth. I'm grateful that I've met a man that has looked into that and we have discovered a lot of new evidence and new witnesses, that now, hopefully, the truth will be told."
That man was Gary Magnesen, a retired FBI investigator who wrote "Investigation: A Former FBI Agent Uncovers the Truth Behind the Most Contested Will in American History."
"I found several new witnesses who testified or have told me that. Howard Hughes left the Desert Inn," Magnesen says. "The aides always testified he never left. I have now found people that contradict that. We've found additional evidence that corroborates their information that they provided me. So now we feel that we have enough evidence to show that he indeed did leave and that Melvin Dummar did indeed pick him up."
After the court ruled against Dummar, he drifted from public view, and over the years, he says he had given up hope of ever claiming his fortune -- until now, as Deiro has come forward to corroborate Dummar's story. He says he secretly flew Howard Hughes to a Nevada brothel that same night.
"I picked up a paper which mentioned for the first time the Cottontail Ranch," Deiros says. "I compared my notes with [Dummar], and I satisfied myself that he did indeed see Howard Hughes."
At that brothel, Hughes liked a certain prostitute named Sunny, who had a diamond in her front tooth, according to Magnesen, who says he is looking for her or someone who knows her.
"She was a lovely woman at the time and we're hoping she's still alive," Magnesen says.
Still, some -- such as Howard Hughes biographer Michael Drosnin -- say the court got it right the first time: The will and Dummar's tale have always been fake.
"The handwriting was not Howard Hughes' handwriting," says Drosnin, author of "Citizen Hughes." "Howard Hughes never left his room. Melvin could not have met him, so his story started out as an obvious lie."
It seems, however, that Dummar may have lied about something. He originally testified that he hadn't been given Hughes' will or read it before it was made public. Then it turned out that he had. Dummar says he had a good reason for not being totally honest about when he read the will. "The main reason ... was because of not knowing the circumstances ... and it actually scared me to death."
Some people wonder why Hughes, whose germophobia was well-known, would want to go to a brothel in the first place.
"He had been with many prostitutes throughout his life, and why he did this, I can't answer that question," Magnesen says.
ABC News attempted to contact both men named as defendants in this lawsuit. Through his daughter, Gay declined to comment, and we were unable to reach Lummis.
ABC News' Bill Ritter reported this story for "Good Morning America."