In a report submitted to the police Monday, medical inspectors said the doctors on duty at the Vinh Long Provincial General Hospital made a professional error when Junior Lieutenant Nguyen Duc Dat had been brought in last July.

The health department wants the hospital to take disciplinary action against the doctors involved.

Vinh Long Provincial General Hospital, where a police officer died of drug overdose. Photo by VnExpress/Cuu Long

The police are set to work with prosecutors and the court to deal with the case, said a province's top police official.

Vinh Long police have given Dat's family VND60 million ($2, 580) in support and buried him at the district's public cemetery.

Dat had been part of a group of police officers who took part in a drug raid July 13. During the raid, he reportedly felt thirsty and drank from a mug he found in a suspect’s house.

Shortly afterwards he started displaying abnormal behavior and was rushed to the hospital screaming and in a state of panic.

Doctors diagnosed him with acute psychiatric illness and sent him to a mental hospital five kilometers (3.1 miles) away instead of giving him emergency treatment.

On arriving at the mental hospital, Dat fell into a deep coma and died after an hour of intensive care.

Test results later revealed that the water in the mug Dat had drunk from contained a large quantity of methamphetamine, and the cause of his death was drug overdose.