The laws are being used with greater frequency in the twilight of the reign of King Bhumibol, 84, and critics say they

are antiquated and being abused for political purposes.Widely referred to as Uncle SMS, Mr. Ampon was repeatedly denied bail despite a history of cancer. The court ruled last year that he was a flight risk and that his condition “did not appear to be fatal.” His lawyer, Anon Numpa, said in a telephone interview on Tuesday that prison may have worsened his condition.

Mr. Ampon complained of stomach pains last week and was sent to a prison hospital, where he died. An autopsy was being performed Tuesday, Mr. Anon said. “His condition would have been better had he been on the outside,” he said.