Sixteen people have been charged in Bangladesh over the horrific murder of a teenager burned to death after reporting sexual harassment.

Nusrat Jahan Rafi, 19, was doused with kerosene and set on fire on the roof of her Islamic school after she refused to withdraw the complaint against her head teacher.

She died in hospital five days after the April 6 attack, with her death sparking mass protests in Bangladesh.

Police described the preparations for the killing as being like a "military plan", with the accused attempting to make it look like a suicide.

Their plan came undone when Ms Rafi - who suffered burns to 80 per cent of her body - was able to give a statement before she died on 10 April.

Headmaster Siraj Ud Doula is among those charged, with police alleging he ordered her murder from prison after she refused to withdraw her accusations against him.

The head of the Police Bureau of Investigation said prosecutors would be seeking the death penalty for all 16 men and women arrested in connection with her murder.

"We will be submitting the charge sheet on Wednesday," Banaj Kumar Majumdar said, reports Nine Publishing .

Women’s rights organisation Bangladesh Mahila Parishad said more needed to be done to ensure the safety of women after a study conducted by the group for 950 women were raped in the country last year.

A study conducted by the group found that about 950 women were raped in Bangladesh last year.

"Justice has to be ensured," a spokeswoman said.