A prosecutor attempted to ensnare Robert Durst in a web of deceit Tuesday after he admitted at his murder trial that he would lie to get out of trouble and had lied under oath in the past.

The New York real estate heir said he hadn't lied during five days of testimony, but a series of inconsistencies during cross-examination in Los Angeles County Superior Court threw his credibility into question and exposed the risk of putting a defendant on the witness stand.

Deputy District Attorney John Lewin, who has long savored the prospect of grilling Durst and said he had a 200-page outline for his questioning, got him to acknowledge there are some acts he would never be honest about.

Lewin asked how jurors were supposed to believe Durst.

“If you’ve said you’ve taken an oath to tell the truth but you’ve also just told us that you would lie if you needed to,” Lewin asked, “can you tell me how that would not destroy your credibility?”

“Because what I’m saying is mostly the truth,” Durst said. “There are certain things I would lie about, certain very important things.”

Durst said he would never admit killing Susan Berman - even if he had done so.

“'Did you kill Susan Berman?' is strictly a hypothetical,” Durst said. “I did not kill Susan Berman. But if I had, I would lie about it.”

Durst, 78, has pleaded not guilty to murder in the point-blank shooting of Berman, his longtime confidante, in her Los Angeles home in December 2000. Durst said he found a lifeless Berman lying on a bedroom floor when he showed up for a planned visit.

Durst said he had prepared for Lewin’s interrogation but was anxious.

“I feel relieved that I’m close to getting this over, and I’m nervous, of course,” Durst told Lewin. “What I want today is to be acquitted.”

Playing clips of interviews Durst gave filmmakers, an interrogation conducted after Durst's arrest in New Orleans in 2015, and clips from his own testimony, Lewin got Durst to acknowledge several lies he told over the years.

Prosecutors say Durst silenced Berman as she prepared to speak with New York authorities about the disappearance of his wife, Kathie, in 1982 and how she provided a false alibi for him.

Durst also acknowledged he wouldn’t admit killing his wife, Kathie Durst, if he had. And he wouldn’t admit murdering his neighbor Morris Black in Galveston, Texas, in 2001 if he had done so.

He has never been charged with a crime in his wife’s disappearance and has denied killing her. Her body has never been found, but she has been declared dead.

Durst was acquitted of murder in Black’s death after he testified that he fatally shot the man during a struggle for a gun. He was convicted of destroying evidence for chopping up the man’s body and tossing it out to sea.

Durst admitted Monday for the first time publicly that he sent police a note directing them to Berman’s “cadaver.” He said he denied sending it for years because it made him look culpable.

During questions from his own lawyer, Durst testified earlier that he had not confessed to any killings when he was captured speaking to himself on a live microphone after filming a documentary about his life and the deaths of people close to him.

In the climactic scene of “The Jinx: The Life and Deaths of Robert Durst,” he could be heard in a bathroom muttering: "What the hell did I do? Killed them all, of course.”

Durst, who had just been caught in a lie about the “cadaver” note, said he either didn’t say everything he was thinking or didn’t speak loudly enough for the mic to catch it.

“What I did not say out loud or, perhaps I said very softly, is: ‘They’ll all think I killed them all, of course,' ” he testified.

Many viewers have interpreted the two sentences, which were edited together by the filmmakers for a dramatic conclusion to the six-part HBO series, as an admission.

Authorities arrested Durst the night before the finale aired in March 2015 because they expected him to flee after the gotcha moment and the unexpected dialogue that followed.

Durst testified that he had been planning to kill himself with a gun when FBI agents apprehended him in the lobby of a New Orleans hotel, where he was registered under an alias.

He told filmmakers that only the killer could have written the cadaver note. His comments off camera came after he was confronted during his final interview for “The Jinx" with a note he had once sent Berman with nearly identical handwriting and Beverly Hills misspelled “Beverley.”

“I wrote this one, but I did not write the cadaver one,” Durst insisted in the film. But moments later, he couldn’t tell the two apart. After an awkward moment blinking and burping, he put his head in his hands. He denied being the killer.

When he stepped off camera - unwittingly still wired for sound - he said: “There it is. You're caught.”

Durst testified that he reached out to the filmmakers to restore his reputation after becoming a pariah following the Texas case.

Despite being a multimillionaire, he was rejected by condominium associations in New York, Houston and California, he said. The Los Angeles County Museum of Art wanted him to make a donation anonymously.

Despite advice from his lawyers not to give a series of interviews for the film project, Durst ignored them.

“That was very, very, very big mistake,” Durst testified.