The Criminal Court yesterday began an inquest into the death of lese majeste convict Ampon Tangnoppakul.
Ampon died while receiving treatment at Klong Prem Central Prison's hospital seven months ago.
The inquest is in response to a petition from Ampon's wife, Rosmalin Tangnoppakul, who claimed her husband died under suspicious circumstances.
Ampon, 61, was serving a 20 year prison term after being convicted on four counts of lese majeste stemming from text messages he sent on his cell phone in 2010.
He died in the prison hospital after complaining of stomach pains.
A police forensic team which conducted a post-mortem said Ampon had died as a result of lung cancer.
Critics say Ampon's death could have been avoided if he had been released and allowed to receive medical treatment elsewhere.
The Ratchada Criminal Court yesterday questioned a prison hospital nurse and doctor about Ampon's death.
Ratchanee Harnsomsakul, 59, a senior nurse who was working at the hospital on May 8 _ the day Ampon died _ said medical staff had provided the "standard treatment" for Ampon, but admitted the prison hospital was not properly equipped to treat cancer patients.
It was also confirmed no doctors were present when Ampon died about 9.10am.
Dr Kittibun Techaporn-anan, 39, the resident doctor, said he was with the hospital director when Ampon died.
He said a ward nurse had contacted him to say Ampon's heart had stopped and they were trying to revive him.
He could not attend to help because he had been instructed by the hospital director to welcome the director-general of the Corrections Department, who was visiting the prison.
The doctor said he had treated Ampon over the previous three days for a stomach complaint.