Indian police have arrested the alleged creator of an app that shared photos of more than 100 Muslim women saying they were on "sale".
Neeraj Bishnoi, 20, is the fourth person to be held in connection with this case.
The app - "Bulli Bai" - was hosted on GitHub, which has since taken it down amid widespread anger and outrage.
This was the second attempt in months to harass Muslim women by sharing their images in a fake auction.
In July last year, an app and website called "Sulli Deals" created profiles of more than 80 Muslim women - using photos they uploaded online - and described them as "deals of the day". Though the police began an investigation, no-one has been charged yet.
Police in at least three states have opened an investigation into the "Bulli Bai" app based on complaints by women who were targeted.
A special unit of the Delhi police that deals with cyber crime arrested Mr Bishnoi in the north-eastern state of Assam on Thursday. "He is the main conspirator, and the creator of the app," KPS Malhotra, the deputy commissioner of the cyber crime team, told the BBC.
Police also said Mr Bishnoi ran the main Twitter handle that shared images from the app.
Earlier this week, Mumbai police arrested three others - Vishal Kumar, a 21-year-old engineering student in the southern city of Bangalore, and two other students, Shweta Singh, 18, and Mayank Rawat, 21, in the northern state of Uttarakhand.
A spokesperson for GitHub said that the company had suspended a user account over the app "all of which violates our policies".
"Our investigation is in its premature stages, so we can't say yet whether "Bulli Bai" and "Sulli Deals" are connected," Mumbai police commissioner Hemant Nagrale told BBC Marathi.
In both cases, there was no actual sale, but the purpose was to degrade and humiliate Muslim women - many of whom have been vocal about the rising tide of Hindu nationalism under Prime Minister Narendra Modi.
"Sulli" is a derogatory Hindi slang term right-wing Hindu trolls use for Muslim women, and "bulli" is also pejorative.
"A few more people have been detained for questioning. We will investigate this case to its logical end," Satej Patel, Maharashtra state's junior home minister, told the BBC.
The list of women on the app included several journalists, a Bollywood actor and the 65-year-old mother of a disappeared Indian student.
The fake auction shocked and angered people after several women who featured on it shared screenshots and messages on social media.
Quratulain Rehbar, a Kashmiri journalist, who had reported on the "Sulli Deals" website last year, said it felt disgusting to be named in the app this time.
Thanks for all the support and messages. If you really care about this issue you must not remain silent because it's not about Indian women or pakistani women. It's about muslim women who are being targetted and it's a clear Islamophobia! #SulliDeals— Quratulain Rehbar (@ainulrhbr) January 2, 2022
Priyanka Chaturvedi, a lawmaker from the Shiv Sena party, told ANI news agency that the new app was created because the makers of the "Sulli Deals" website hadn't been punished yet. The parliamentarian also shared letters written to Mr Vaishnav after the website came to light in July 2021.
When news of the app broke, poet Nabiya Khan who was targeted last year tweeted that the Delhi Police had yet to take action on her complaint in 2021.
Hi @DelhiPolice. This lot already harassed me by hosting an auction of me and making disgusting lewd comments on me. I had filed an FIR in May with you, but you’ve done absolutely nothing. Now they’re back with this. Good job protecting women. Will you do anything now atleast? https://t.co/HvMlIIho7N— Hasiba | حسيبة | हसीबा 🌈 (@HasibaAmin) January 1, 2022
A 2018 Amnesty International report on online harassment in India showed that the more vocal a woman was, the more likely she was to be targeted - the scale of this increased for women from religious minorities and disadvantaged castes.
Critics say trolling against Muslim women has worsened in recent years in India's polarised political climate.