LAS VEGAS — Margaret Rudin's alleged paramour took the stand for the prosecution Tuesday afternoon, but what he said about the so-called Black Widow was far less important than what the district attorney said about him.

As a rapt jury looked on, prosecutor Gary Guymon charged that Rudin's companion, Yehuda Sharon, disposed of her slain husband's body, doctored a gas station receipt to support his alibi and then offered to "crack the case wide open" for $1 million.

"This must've been some very good information you were willing to sell," Guymon snapped at Sharon. Rudin's defense lawyers were livid at Guymon's attacks on the witness and complained to Judge Joseph Bonaventure that the prosecution was trying to trap Sharon and "poison the jury."

The prosecution contends that Sharon, a holy oil salesman who also goes by the name Eugene Warner, helped the 57-year-old socialite kill her fifth husband in a bid to inherit part of his $11 million fortune. The charred remains of Ron Rudin, a real estate developer and gun dealer, were discovered in January 1995 at a remote desert location known as Nelson's Landing. Detectives suspected Rudin shot him as he slept in their home and then Sharon dismembered his corpse and drove it to the desert in a rented van.

The district attorney's office gave Sharon immunity in 1995 in exchange for his cooperation, but he said then and maintains now that he knows nothing of the murder, never had a romantic relationship with Margaret Rudin and rented the van for a business trip to Lenwood, Calif.

When the prosecution called Sharon late Tuesday, jurors seemed to snap to attention. The panel had just completed listening to the third DNA expert, testimony which even the judge observed the jury seemed to find boring. Since the beginning of the trial, now entering its second month, the jury has heard references to Sharon and seen pictures of him, including a shot of him looking handsome and strapping in his military uniform.

The man who entered court was older and smaller than his photos. Sharon spent the first part of his testimony outlining the trip Lenwood. Guymon tossed him one softball question after another, and Sharon gave long-winded, rambling answers in his thick Israeli accent.

"Every time His Holiness makes a trip I jump," he offered during one disjointed explanation of how his business was affected by Pope John Paul II's trip to the Philippines.

He said he had rented a car on Dec. 18, 1994, the day Ron Rudin disappeared, to go to Arizona to buy bottles for the chrism he sells to churches. But he later discovered that the bottles were only available in California and only in large quantities so, he claimed, he traded the car in for a van Dec. 19.

Sharon said that on Dec. 22, he set out for Santa Fe Springs, Calif., but turned back when he reached a gas station in Lenwood because it was drizzling and a truck driver he met said more rain was ahead. Sharon said he bought gas and food and then headed back to Las Vegas. He said he had kept the receipt from the gas station and in 1995 gave the original to Rudin to pass on to her attorneys. That original was lost, he said, but he kept a copy of it which he gave to the prosecution and the defense about three months ago.

When Sharon's account was done, Guymon placed a blow-up of the receipt before the jury and began trying to dismantle the witness's story. The prosecutor told Sharon the price of gas listed on the receipt — $1.15 — was wrong for Dec. 22, 1994, but exactly right for two years later.

"I have no idea because I really don't pay attention to gas prices. I know the octane I need and that's it," Sharon said.

Guymon pressed on, saying he would call a witness who would testify that the "Welcome to the Lenwood AM-PM" message on the top of the receipt was part of the receipt design in 1996, but not in 1994. He also showed Sharon weather reports indicating that no rain, nor drizzle fell in that part of California on Dec. 22, 1994.

"Isn't it true that this is a receipt from Dec. 22, 1996?" he asked

"Not that I'm aware of," Sharon replied.

With the defense loudly objecting, Guymon asked, "Isn't it true you went to Nelson's Landing with that van and not to Lenwood?"

Sharon denied the charge, but Guymon had him declared a hostile witness and grilled him further. The prosecutor reminded him that the immunity deal did not extend to perjury charges.

"You cannot lie under oath with immunity," Guymon said.

"I have no intention," Sharon replied.

The prosecutor also confronted him about offering to sell his testimony for $1 million.

"There is an explanation. There is a qualification. It is not a yes or no [question]," Sharon hedged. But he acknowledged that he told detectives in 1997 that he would "crack the case wide open" in exchange for money. He added cryptically that he was trying to "get out of circumstances."

Rudin's lawyer, Michael Amador, had only begun cross-examining Sharon when court broke for the day. Outside the jury's presence, the defense griped about a lack of foundation for some of Guymon's questions and asked that Sharon's testimony be stricken. Bonaventure denied the motion, but said he anticipated a long day of legal wrangling when the witness's testimony continues Wednesday morning.

"We're going to have a tough time with objections tomorrow. We're going to have more fights tomorrow," he predicted.