Joran van der Sloot, the main suspect in the 2005 disappearance of Alabama teen Natalee Holloway, has been moved to a remote Peruvian prison after he allegedly threatened to kill the warden at the prison where he was initially serving a 28-year term for murder. Van der Sloot, 27, was moved Sunday from the prison north of Lima to Challapalca, located high in the Andes near the Bolivian border, according to the Associated Press.

Van der Sloot's lawyer said his client had "a problem with the director" at the prison near Lima, according to BBC News. To protest the prison transfer, Van der Sloot has gone on a hunger strike. Van der Sloot, a Dutch citizen, was sentenced in 2012 after pleading guilty to strangling, beating and suffocating Stephany Flores,  a 21-year-old Peruvian business student he met in a casino. He was the last person seen with Holloway, who disappeared while on a graduation trip to Aruba. She was 18 at the time.

Holloway’s body has never been found and Van der Sloot has denied any involvement in her disappearance. U.S. officials have said they will extradite Van der Sloot for questioning about the Holloway case after he finishes serving his sentence in Peru.