The suspect took Samia Afrin Saima to the roof of the eight-storey building, saying that he would show her the view and raped the seven-year-old girl inside an empty flat.
When the girl passed out, he strangled her with a rope and dragged the body to the kitchen.
The suspect, Harun Or Rashid, disclosed these to the detectives after he was arrested in Cumilla yesterday.
“Harun admitted that he had killed her alone after raping her… He killed her so that she cannot disclose his identity,” Abdul Baten, additional commissioner of Detective Branch of Dhaka Metropolitan Police, told a press conference at the DMP Media Centre.
Harun, aged around 25, had moved in with his cousin Parvez’s family at their flat on the 7th floor of the building at the capital’s Wari two months ago.
Saima and her parents lived on their flat on the 5th floor of the building. The nursery student of Silverdale Preparatory and Girls’ High School often went to Parvez’s flat to play with his son and knew the suspect, Baten said.
On Friday, Saima left their flat telling her mother that she would return in 10 minutes.
Harun met the girl in the lift and asked her to go to the roof with him.
After killing the girl, Harun fled to his village home in Cumilla’s Dabordanga area, the additional commissioner said.
When Saima did not return home, her family started looking for her and found her body inside the empty flat about an hour later.
After autopsies, forensic experts said the girl had been raped before she was killed.
The murder shook the country to the core, triggering protests by students, teachers and parents.
“I could not save my daughter… Now the time has come for girls’ parents to think how they can save them from such brutes,” Saima’s father Abdus Salam told reporters as he broke down in tears.
The grieving man also said many other murders had been forgotten and covered up and urged people to make sure that that did not happen again.
“We want quick trial. We want to see the killer awarded the highest punishment in six months,” he said.
Saima’s fellow students, their parents and teachers demonstrated in Wari, demanding immediate arrest and capital punishment of the killer yesterday morning.
Chanting slogans, they marched to the Wari Police Station in the rain and staged a sit-in in front of the police station. They also handed a memorandum to the officer-in-charge.
“How do we feel safe when the life of a girl like Saima is not safe in the society… This type of crime will continue if the perpetrators go unpunished,” Sworna Saha, a student of the school, told The Daily Star.
“We want to grow up without fear,” said 9th grader Samia Jannat.
Citing Tonu murder in Cumilla and Nusrat Jahan Rafi murder in Feni, another student Khusbu Akter Neha said the culture of impunity was leading to the recurrence of such crimes.
“We want people to treat us as human beings, not as girls,” she said.
Different organisations also expressed grave concern and demanded justice for all such incidents.
The Manusher Jonno Foundation in a statement urged the government to take effective steps to prevent violence and torture on children.
Its Executive Director Shaheen Anam called for forming committees in every neighbourhood to prevent rape.
The incidents of violence against women and children have reached an unbearable level due to lack of justice, said the statement, adding that rape leaves short- and long-term impact on a child’s physical and mental health and on their social lives.
At least 399 children were either raped or subjected to attempted rape in the first six months of this year, it said, citing newspapers.
Of them, 16 were killed after rape and 49 children were harassed sexually.
In another statement, Naripokkho demanded a separate law to stop sexual harassment.