His father Faizuddin Ahmed filed the case against some unknown people, said Inspector Faruk Molla.
Mohammad Rezaul Karim Sabuj, brother of the victim, said Anisul was posted at BMP as assistant commissioner (traffic). On Monday morning, he was brought to Dhaka National Institute of Mental Health and Hospital (NIMH) from Barishal around 6:30am as he has been suffering from mental illness.
From there, Anisul was taken to Mind Aid Hospital in the city's Adabor area around 11:30am. He was taken to the National Institute of Cardiovascular Diseases where doctors said Anisul had died before being brought here.
When Sabuj informed police, they collected the CCTV footage of the hospital which showed some people dragging Anisul and beating him up while being taken to the washroom.
Sabuj said his brother was killed by the staff of Mind Aid Hospital.
Police’s Deputy Commissioner (Tejgaon Division) Harun-or-Rashid told UNB that they are scrutinising the CCTV footage of the hospital.
“Investigations are going on and action will be taken. Several people, including the manager of Mind Aid Hospital, have been detained in this connection,” he said.
Meanwhile, Anisul was laid to rest at the central graveyard of Gazipur city after a namaz-e-janaza at Bhawal Rajbari field on Tuesday morning.
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