Police could not discover the circumstances surrounding the death of Sadman Sadiq Sarker nicknamed Arian, son of Selim Sarker, a receptionist of Monwara Hospital in Ramna.

Police arrested a home help at a four-storey building, but she denied her alleged role in the killing, saying she even did not know the boy.

Selim, his wife Kamrunnahar Lipi and their son Sadman lived in a sublet room on the second floor of the building owned by Zinnat Hossain. The family they lived with went to their home village three days ago.

"My wife went shopping at 9:30am. She left home, latching the door from outside. My son and I were back at home," Selim told The Daily Star, adding the gate of the building remains locked round the clock.

An unknown person pressed the doorbell at about 9:45am, but Selim found no-one downstairs. "I went to the bathroom and came out in three minutes only to find the door open. I found Sadman nowhere," said Selim, disconsolate with grief.

Sadman's mother said she found Mariam, domestic help of a third-floor tenant, at the entry to the building when she was going to the market. "But her employers said she (Mariam) did not come (yesterday)," she said, hinting at Mariam's role in the kidnap.

Police retrieved the body with head and shoulder injuries -- eyes and legs blood-stained.

Sadman's parents rushed him to Monwara Hospital where doctors confirmed his death. Ramna police took the body to Dhaka Medical College Hospital for an autopsy. Sadman was buried in his home village in Debidar in Comilla.