Nguyen Xuan Quy, 38, and four others are being investigated for allegedly storing, buying and using drugs, Hanoi police said Wednesday.

Quy has received treatment at the National Mental Hospital since November 2018.

During his term at the hospital, Quy has escaped numerous times. In January, he was arrested by police in Hai Ba Trung District, but released back to the hospital due to his condition.

Quy has formed close relationships with certain hospital staff, who afforded him privileges regarding accommodation and travel, among others. Using this to his advantage, Quy soundproofed his room, equipping it with loudspeakers and strobe lights for recreational purposes.

On March 20, Hanoi police raided several hospital rooms, including Quy’s, seizing around 6.1 kilograms of ketamine, meth and MDMA. They also found bongs, DJ tables, laptops and hundreds of plastic bags.

Police later discovered Quy, besides takings drugs, had also sold some to other patients and staff.

Vuong Van Tinh, hospital director, said the facility did not know about Quy’s wrongdoing, and that it was waiting on further police information.

Nguyen Truong Son, Deputy Minister of Health, on Tuesday said the incident was "unacceptable" and those involved would be strictly punished.

Besides Quy, Nguyen Anh Vu, a technician at the hospital who had tested positive for drug use, has also been detained for not informing authorities of Quy’s crimes.