EXCLUSIVE: Allegations of witness tampering in Hillsborough murder case

HILLSBOROUGH, Calif. (KGO) -- ABC7 News has learned exclusively of new allegations of witness tampering in the Hillsborough mansion murder case. The allegations involve the prosecution's key witness in the case against Tiffany Li and her boyfriend Kaveh Bayat in the 2016 murder of Keith Green, the father of Li's two children.

The witness in the case, bodyguard Olivier Adella, cut a deal with the San Mateo County District Attorney's Office in February that will result in prosecutors potentially dropping the murder charge against him in exchange for his truthful testimony against Li and Bayat.

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As part of the deal, Adella pleaded no contest to accessory after the fact.

Adella helped dispose of Green's body in a remote area of Sonoma County near Healdsburg. He told ABC7 News that he agreed to do it out of fear for his life and his family's safety and he believed that if he didn't cooperate, the couple would try to pin the murder on him.

Adella's attorney says his client recently came to him with stunning news.

"He tells me that there's an inmate on his side of the jail who has told him that Mr. Bayat has offered him money to testify that Adella says that he actually killed Mr. Green and that Adella's wife was involved," said Dek Ketchum, Adella's Attorney.

The bribe was allegedly for $1 or $1.5 million dollars.

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Ketchum reported the allegation to the sheriff's office which then conducted an investigation.

"The conclusion was that the evidence was not sufficient in order to file charges for this," said District Attorney Steve Wagstaffe.

The District Attorney says it wasn't clear where the money for the alleged bribe would come from.

"Other than of course everyone knows that Ms. Li comes from a very wealthy family," said Wagstaffe.

Tiffany Li's attorney Geoff Carr tells ABC7 News, "We don't know about the veracity of the accusation and we had nothing to do with it."

Kaveh Bayat's attorney James McNair Thompson strongly denies Bayat is involved in witness tampering and tells ABC7 News Adella and the inmate who made the allegation are friends who "cooked up" the story to harm Bayatt.

Thompson also tells ABC7 News, "In addition to voluminous evidence that Adella is in fact the one who shot Mr. Green, Mr. Adella was given a polygraph test by the prosecution, using their expert polygrapher.

"He was asked, 'Did you shoot Green?' He answered 'No.' The polygrapher said Adella was not being honest. After a short time, the polygrapher again asked Adella if he shot Green, Adella again said 'no' and the polygrapher again said Adella was lying.

"I am very troubled by the fact that the prosecution is using a person who the evidence shows is the actual killer of Mr. Green, and whose guilt is confirmed by the polygraph examination, as a witness to say that Mr. Bayat shot Mr. Green. They then intend to let the killer go scot-free once they have convicted an innocent man. Nevertheless, we are not manufacturing evidence of Mr. Adella's duplicity. We don't need to. It is Mr. Adella who is manufacturing evidence."

"What goal would that accomplish for Mr. Adella, he's already got a deal and if he tells a lie at any point his deal is off," said Wagstaffe.

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ABC7 News spoke with the inmate who made the allegation. He tells ABC7 news that Bayat offered him half of the $1.5 million before he testified against Adella and the rest to be paid after his testimony. He says that when the offer was made, he at first told Bayat he would do it. A few days later he told a representative of Bayat's defense team of the bogus confession when the representative showed up at the jail to talk to him, apparently at the direction of Bayat.

"They just showed up and said, 'I hear you have something to tell us,"' the inmate said.

The inmate says he felt guilty afterwards and told Adella what he had done. Adella then told his attorney.

Li is out after posting 65 million dollars bail in cash and property. Bayat remains in jail. The trial for both is scheduled to start in September.

Adella has been moved to a different facility for his safety.

Click here for full coverage on the investigation into the death of Millbrae father Keith Green.