Paul Rusesabagina, the former hotelier who inspired the acclaimed 2004 film “Hotel Rwanda,” claims he was tortured for several days by Rwandan authorities at an unknown location he described as a “slaughterhouse” after inadvertently traveling to Kigali last August and being arrested.

Details of the treatment that Rusesabagina, a 66-year-old cancer survivor, claims he received when he first arrived in Rwanda’s capital were revealed in an affidavit of one of his Rwandan lawyers, Jean-Felix Rudakemwa. The affidavit, dated May 3, includes a memorialization of a conversation Rudakemwa claims he had with Rusesabagina in the Kigali prison, where he has been detained for nearly nine months while facing terrorism-related charges. In the affidavit, Rudakemwa states that he intended to have Rusesabagina sign a formal statement, but the situation at the prison “has deteriorated considerably, to the point where I am no longer allowed to visit him with privileged and confidential material in my possession.”

The documents were submitted by Rusesabagina’s family and legal representatives on Tuesday in order to update the complaint they filed with the United Nations Special Rapporteur on Torture and Other Cruel, Inhuman, or Degrading Treatment or Punishment last September. The new documents were part of an urgent appeal to the special rapporteur, Nils Melzer, to help secure Rusesabagina’s release.

“We caution that we have a good faith basis to believe that the extent of the torture suffered by Mr. Rusesabagina is greater than that revealed,” Rusesabagina’s international counsel said in a letter addressed to Melzer on Tuesday. “We believe the same about the nature and extent of his injuries.”

Rusesabagina, who is originally from Rwanda but is a Belgian citizen and permanent resident of the United States, traveled to the United Arab Emirates on Aug. 27 to meet with Constantin Niyomwungere, a Burundi-born pastor who Rusesabagina claims invited him to speak about his experiences during the Rwandan genocide at churches in Burundi. According to Rusesabagina’s international legal team, the pair hopped on a private jet that Rusesabagina believed would take them from Dubai to Burundi’s capital, Bujumbura.

Rusesabagina had no idea the pastor was an informant for the Rwanda Investigation Bureau and had duped him into flying to Kigali on a chartered flight.

“Myself, the pilot, and the cabin crew were all aware that we were heading to Kigali,” Niyomwungere told Rwanda’s high court in Kigali earlier this year. “Paul was the only one who didn’t know where we were going.” Prosecutors in Rwanda allege that Rusesabagina intended to travel to Burundi to coordinate with rebel groups based there and in the neighboring Democratic Republic of the Congo.

According to the affidavit, Rusesabagina informed his lawyer that the pilot and flight attendant both stated that they were flying to Bujumbura. Rusesabagina said he didn’t realize they were at Kigali International Airport until the plane touched down early on Aug. 28. According to the affidavit, Rusesabagina then began screaming and attempted to exit the plane, but was restrained by Rwanda Investigation Bureau agents.

Rusesabagina’s international legal team believes the plane was operated by GainJet, which has previously been used by the Rwandan government and has an office in Kigali. Rusesabagina’s family has filed a lawsuit against the Greek air charter company for allegedly assisting Rwandan authorities in kidnapping him.

According to the affidavit, Rusesabagina told his lawyer that he was taken to an unnamed facility and was blindfolded and bound at the hands and feet until Aug. 31.

Rusesabagina claims he was denied food and sleep while at the “slaughterhouse,” and that he was not allowed to communicate with his family or lawyers. He claimed that his nose and mouth were also covered at times. When his legs shook from a lack of oxygen, Rusesabagina said a Rwanda Investigation Bureau agent would release the gag so he could breathe.

Rusesabagina recalled one incident in which a Rwanda Investigation Bureau agent was accused of stepping on his neck with military boots. Rusesabagina stated that he was “barely breathing” at the time, but could hear the agent say, “We know how to torture.” Rusesabagina also stated that he was unable to stand on his own and that he needed to be held whenever he had to defecate.