By Brian Melley

LOS ANGELES (AP) --

Robert Durst testified Tuesday that he was not confessing 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," the New York real estate heir 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 that implicated him in the killing of his best friend, 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 impromptu dialog 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.

The testimony came on Durst's fifth and final day of questioning by his defense lawyer during his murder trial in the killing of Susan Berman at her Los Angeles home in December 2000. He has pleaded not guilty and repeatedly denied shooting her.

Deputy District Attorney John Lewin began a cross-examination that is expected to be lengthy. Lewin said he had a 200-page outline of what he planned to ask Durst.

Durst said he had prepared for Lewin's questions but was anxious.

"I feel relieved that I'm close to getting this over, and I'm nervous, of course," Durst said. "What I want today is to be acquitted."

Prosecutors said Durst silenced Berman — his confidante — 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, 78, admitted publicly for the first time Monday that he had sent police a note with the word "cadaver" that directed them to Berman's house after she was killed. He testified that he found her dead on a bedroom floor when he arrived at her house for a planned visit before Christmas. 

He said he sent the anonymous note because he feared being implicated in the slaying. For decades, he maintained the lie that he didn't write the note. 

He told filmmakers that only the killer could have written the 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 being acquitted of murder in the Texas killing of his next-door neighbor in a Galveston apartment. 

Durst said he was a pariah after he testified that he killed Morris Black in self-defense and then panicked and chopped up the man's body and tossed it out to sea. 

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

Despite advice from his lawyers not to give a series of interviews, Durst said he went ahead with the project.

"That was very, very, very big mistake," Durst testified.

MySHOOT Profiles