Earlier this week, several Muslim women in India found out that they were offered for sale in fake "auctions" online without their knowledge. Pictures of over 80 women were reportedly uploaded to a software development platform, GitHub, under the title "Sulli deal of the day". "Sulli" is derogatory slang for Muslim women.

One of them was airline pilot Hana Mohsin Khan, who was alerted last week by a friend who directed her to a link that led to a gallery of images of women.

"The fourth picture was mine. They were literally auctioning me as their slave for the day. It sends chills down my spine. From that day till today, I am just in a constant state of anger," Khan told AFP. 

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She told BBC that she also saw photos of her friends on the first two pages. 

"I counted 83 names. There could be more. They'd taken my photo from Twitter and it had my user name. This app was running for 20 days and we didn't even know about it," she told BBC.

Online harassment of women and girls -- including threats of violence, rape and manipulated pornographic images -- is a huge problem, not just in India.

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Khan believes Muslim women are a particular target of online harassment. 

"I'm a Muslim woman who's seen and heard. And they want to silence us," Khan told BBC.

Sania Ahmad, another woman who found her photo on the app, also believes that she was targetted because she was Muslim. 

"It starts with petty abuse and grows into death and rape threats.  I have 782 screenshots of abuse -- mostly on Twitter -- targeted at me. And these are just from the past year," she told AFP. 

Meanwhile, GitHub said it has now suspended the users' accounts, saying they violated its policies on harassment, discrimination and inciting violence.

Delhi police have filed charges in connection with the case-- but against unknown persons because they do not know the identity of the perpetrators.