Karl Joseph Kraus died on Thursday while awaiting trial on charges of raping four sisters aged between 7 and 15 at his home in Doi Saket, according to the Phuket News.
Seated in a wheelchair, Kraus made his first court appearance iin Chiang Mai on April 30 last year. His lawyers argued that he was not fit to stand trial because he was suffering from dementia and cancer.
Kraus was originally arrested in 2010. Parents of the four sisters claimed he had lured the girls to his house by offering them English lessons, money, and chocolate.
Germany-born Kraus, a former railway worker from Sydney who lived for a time in Western Australia, was accused of abusing the four sisters for almost two years.
Arresting officers also found child pornography on Kraus's computer. Authorities said he faced up to 20 years in jail if convicted.
He pleaded not guilty to rape and sexual assault.
Following his arrest Kraus was granted bail of 400,000 baht but fled to Myanmar. Authorities there arrested him in August 2012 for lacking a valid visa and sent him back to Thailand, where he was locked up for jumping bail.