Image copyright Getty Images Image caption Images of the alleged rape victim and her mother caused outrage in Bangladesh

Four men have been arrested in Bangladesh over the alleged rape of a student, after pictures of her with a shaved head were shared online.

Police said Tufan Sarker, a unionist linked to the governing Awami League party, was among those detained.

A manhunt is under way for Mr Sarker's wife, Asha Khatun, who is accused of beating the 16-year-old and her mother and shaving their heads.

The photos caused outrage in Bangladesh and authorities were urged to act fast.

Mr Sarker, 25, was charged on Friday by police from the Bogra district with raping the girl and threatening to kill her, officials said.

"He threatened to kill her and her mother if she would dare to talk to anyone about the incident," local police spokesman Sonaton Chakroborty told AFP news agency.

Another officer said that Mr Sarker was the local leader of the labour wing of the Awami League, which came to power eight years ago.

The other three men arrested are accused of abetting the rape.

Photos of the alleged victim and her mother under police protection at a local hospital spread quickly online, shocking the Bangladeshi public.

The alleged victim, whose identity has not been disclosed, said Mr Sarker's wife suspected she had engaged in a relationship with her husband.

"They shaved my entire head. I repeatedly apologised but they didn't listen. They even beat my mother and shaved her head," she told local media.