Former Goldman Sachs Group Inc banker and convicted 1MDB conspirator Roger Ng described living in the Sungai Buloh Prison prior to his extradition to the United States as “absolute hell” and punishment enough for his crimes.

In a letter to US district judge Margo Brodie, in which he is pleading for leniency ahead of his sentencing next week over his role in the 1MDB saga, Ng recounted harrowing tales during his time at the prison.

He said he was made to sleep on cement floors while living with rats and other vermin and also contracted malaria and leptospirosis, a bacterial infection spread through contact with rat urine.

A Bloomberg report said Ng, in a court filing, related how he had spent six months in prison, where he was chained to as many as 20 other prisoners.

He also claimed that he was held in solitary confinement for up to two weeks at a time.

“Six months in the Malaysian prison had a devastating effect mentally and physically.

“Until today, I find myself reclusive socially as I continue to deal with this brutal and distressing experience. The time without sunlight and in isolation made me lose my mind and become frightful,” he was quoted as saying.