Van Der Sloot, 23, is behind bars awaiting trial over the murder of a Peruvian woman.
According to Dutch magazine Panorama, he has been involved in a string of violent confrontations inside Lima's Castro Castro prison, one of which left another inmate requiring emergency treatment.
Van der Sloot's lawyer has denied the allegations, describing them as "fabricated."
Panorama also alleged that van der Sloot has been a heavy drug user while in jail. "He has been put into solitary confinement several times but comes out even more angry," a source told the magazine.
The article was followed up by Dutch newspaper De Telegraaf Wednesday. It said it had put the allegations to his lawyer, Maximo Altez, who dismissed them. "There are bad intentions to do harm to Joran," Altez said. "But he actually wants to change his life and goes to church."
Van der Sloot has been held in custody since June 2010 over the murder of 21-year-old Stephany Flores. The Dutch national is accused of robbing and killing Flores in his Lima hotel room in May 2010.
Van der Sloot remains the chief suspect in the disappearance of Holloway, an 18-year-old student from Mountain Brook, Ala., who disappeared in May 2005 during a high school graduation trip to Aruba.