Representatives from a hospital that treats people with mental disabilities have appeared in court to answer questions from the family of a dead man who say they should have been consulted before he was given a controversial treatment.

The people's court in suburban Changping district heard that Hao Lei, 20, from Shaanxi province, died suddenly because of phenothiazine, an organic compound that occurs in various anti-psychotic and anti-histaminic drugs. He passed away on June 26, two months after leaving his hometown to seek work in the capital.

The medical records from the Red Cross Beijiao Hospital, which is now named the Huayi Hospital, show that doctors prescribed 50 ml of phenothiazine three times a day from June 21 to June 24 and 100 ml three times a day from June 24 to June 26.

Chen Jihua, from the Weikai Law firm, said the use of the drug was unreasonable because it has not been widely used since the 1950s. The medical reports from the hospital also show that Hao had been restrained after he was hospitalized on June 21.

"Even without the medicine, my son could have died because he was tied to the bed for five days," said Hao Lei's father, 46-year-old Hao Husheng, who is seeking about 659,700 yuan in compensation.

The court also heard that Hao's body was bruised.

Research from the Technical Appraisal Institute of Forensic Science affiliated to China University of Political Science and Law said the injuries were not the main reason why he died.

"A doctor later told me they could not reach the family members before the treatment and the call to inform us about his death was a coincidence," Hao's father said.

The hospital refused to disclose any details or comment on the death.

However, its treatment did not appear to be in line with its own diagnosis. According to Beijing News, the hospital gave Hao a treatment before building up a clear understanding of his medical history and finding out what mental disorder he had.

His father insisted he did not even have a medical condition when he left home.

"Hao Lei had been healthy and had no mental disease," he said. "He did not even smoke and drink."

The young man traveled to Beijing looking for work with 400 yuan in his pocket on April 19. It was the first time he had left his village in Shaanxi province.

The court heard he only phoned home once after his arrival.

"He told his grandfather he had been cheated on June 18 and soon after the phone was cut off," said his father.

Two days later, police officers took him to the hospital where he was described as "a homeless mental patient".

The work log from the officers at the Shibalidian police station shows that they found him bleary eyed and with slurred speech near a village in Chaoyang district. The log said he took off all his clothes and walked around naked at the police station.