In video, Joran van der Sloot appears to confess to Natalee Holloway's murder, lawyer denies it

(FOX NEWS) - Joran van der Sloot's lawyer is disputing a video posted online Wednesday showing the convicted Dutch killer allegedly admitting to killing U.S. teen Natalee Holloway more than a decade ago in Aruba.

Van der Sloot's lawyer, Maximo Altez, told Fox News Latino that the admission, recorded surreptitiously in prison during an inmate visit, is a fabrication.

"It's a total lie, it's a distorted, the video has been edited to make it look like that," Altez said.

The recorded interview, in Dutch, is conducted by an unidentified male. It appears to have been taken with a hidden camera and at one point it shows van der Sloot's Peruvian wife and mother of his child, Leidy Figueroa, sitting by his side. They are holding hands.

For the most part of the edited video, which is shown with English subtitles on Radar Online, van der Sloot talks about the incompetence of the investigators that handled the Holloway case.

"I think that was one of the worst police investigations that ever took place!" reads the translation on the screen.

The unidentified interviewer then asks, "Are you talking about the Holloway case?"

"Yes yes yes," van der Sloot responds. "Yes, this is also where I am guilty and I admit everything that I have done."

Van der Sloot remains the chief suspect in the May 2005 disappearance of the Alabama high school senior, who was last seen while vacationing in the Caribbean island.

Altez said his client, whom he is counseling pro-bono, is a "compulsive liar" with a verifiable psychiatric diagnosis.

"He can confess to killing John Kennedy, or John Lennon, that doesn't mean he did it," Altez said in a phone interview. "He is a mythomaniac."

He also said the supposed confession has no legal standing because it was not made before a court of law.

Van der Sloot is serving a 28-year sentence in the Challapalca prison in Peru, nicknamed the "Alcatraz of the Andes," for killing 21-year-old Peruvian Stephany Flores in her hotel room in 2010.

While in prison, Van der Sloot met and married Peruvian Leydi Figueroa and they had a daughter, who is now 18 months old.

Figueroa told Fox News Latino that she was "surprised" to hear about the alleged confession.

"It doesn't make any sense for Joran to say something like that," she told FNL on Thursday.

She said she helped coordinate the interview, which she said took place in late January and lasted for about two hours. According to Figueroa, van der Sloot agreed to the interview because "he considered this journalist as family." She, however, would not name the alleged reporter conducting the interview.

"I am very angry because he shouldn't have brought a camera inside," she said, adding that she is planning to file a complaint with the Peruvian Penitentiary Institution (INPE). "They are supposed to check that no cameras get in."

Van der Sloot, 29, is one of only two foreigners in the Challapalca prison and he has repeatedly claimed through his lawyer that because he is "famous" he is a constant target of the other inmates in search for a quick buck.

The convicted Dutchman was transferred to the remote, icy penitentiary in southern Peru in August of 2014 after allegedly starting a fight with another inmate in the Lima prison where he was serving his term. Peruvian authorities said he also threatened to kill the warden of the prison.

After multiple legal motions, Altez said he expected his client to be transferred back to a more low-security prison in Lima as soon as May.