Joran van der Sloot, the Dutch national suspected in the 2005 disappearance of Natalee Holloway who will soon arrive in the U.S. to face charges that he extorted her mother, once claimed that he had shoved the Alabama teen to the ground so hard she that hit her head on a rock and died, according to court documents.

However, van der Sloot, who was convicted in 2010 of a woman's murder in Peru, has shifted his story about Holloway's case for years and is described by his own lawyer as "an ill person" with "psychological problems." He even told interviewers over the years that some of his past changing stories had been lies.

As part of the alleged $250,000 extortion plot, van der Sloot allegedly told a lawyer for Beth Holloway, Natalee's mother, that the 18-year-old's body was buried inside the foundation of a house in Aruba, the Caribbean nation where she vanished on May 30, 2005, during a high school graduation trip.

"Van der Sloot went on to admit that he had been with Natalee on the night of May 29/30, 2005, and that he had thrown her to the ground after she had attempted to stop him from leaving her," page six of a federal affidavit alleges. "Van der Sloot claimed that when she fell down, she hit her head on a rock and died as a result of the impact."

NATALEE HOLLOWAY, SUSPECT JORAN VAN DER SLOOT: TIMELINE OF ALABAMA TEEN'S DEATH

Joran van der Sloot

Joran van der Sloot is the prime suspect in the 2005 disappearance of Natalee Holloway. He is serving a prison sentence in Peru for murdering a 21-year-old woman named Stephany Flores in 2010.  (Getty Images, AP)

Then, he allegedly enlisted his father's help to hide the body. However, he led the Holloways' lawyer to the location, and no body was found, according to federal prosecutors. Then, after the lawyer left Aruba, van der Sloot allegedly told him that he had lied about the location. 

Paul van der Sloot, an Aruba judge and the suspect's father, died in 2010.

No one was ever prosecuted in connection with Holloway's disappearance, although van der Sloot and two of his friends, Satish and Deepak Kalpoe, were arrested and released due to lack of evidence more than once.

Read the affidavit (Mobile users go here)

NATALEE HOLLOWAY SUSPECT JORAN VAN DER SLOOT GETTING DIVORCED AFTER PRISON DRUG SMUGGLING SCANDAL

He was indicted on charges of extortion and wire fraud in a federal court in Alabama in 2010 after allegedly trying to squeeze cash out of Holloway’s family in exchange for the location of her remains.

That same year, he killed Stephany Flores, a 21-year-old business student in Peru, after meeting her in her father's casino in Lima.

Natalee Holloway and friends smile

Natalee Holloway, center, went missing during a spring break trip in 2005 and was never found. The prime suspect in her disappearance, and suspected murder, is Joran van der Sloot, who will be sent to the U.S. from prison in Peru to face trial after allegedly extorting her mother. (FBI)

Van der Sloot is serving a decades-long prison sentence in the South American country but will be temporarily sent to the U.S. to stand trial on the extortion charges before returning to Peru to finish his sentence there.

If convicted in federal court in Alabama, he would be sent back to the U.S. in 2038 to serve up to 40 more years in an American prison. As part of the preparations for the temporary transfer, he was shipped from the mountaintop Challapalca prison Thursday to one in Lima, near the airport, from where the FBI is expected to escort him to the U.S.

Joran Van der Sloot is escorted by police officers to the airport in Santiago

Joran van der Sloot is escorted by police officers to the airport in Santiago June 4, 2010. He was arrested twice over the disappearance of Natalee Holloway in Aruba in 2005, and five years later murdered Stephany Flores in Peru. (REUTERS/Victor Ruiz Caballero )

Holloway, an 18-year-old from Mountain Brook, Alabama, a suburb of Birmingham, flew to Aruba with a large group of friends ahead of their high school graduation.

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On May 30, 2005, some friends went out to a nightclub and met van der Sloot, who was also 18 at the time. He and Holloway were seen leaving the bar together. That was the last time she was seen.

In 2012, an Alabama judge declared her legally dead. Her remains have never been found.

She would be 36 years old today.

Through his Lima-based attorney, Maximo Altez, van der Sloot maintains his innocence.