Police arrested a suspect in Islamabad after a harrowing video of him torturing and stripping a woman and a man went viral on social media, it emerged on Wednesday.

According to the FIR registered on July 6, a copy of which is available with Dawn.com, the incident took place within Golra police station limits at an apartment building in sector E-11/2. The case was registered on the complaint of a sub-inspector.

"The video of the incident went viral on social media. In the video, five to six men can be seen keeping the victims in custody under gunpoint. The accused also stripped the man and the woman naked while threatening them," the FIR said, adding that the suspects were also doing "vulgar acts".

One clip of the video shows a group of men with weapons, led by Usman, threaten the man and woman with physical harm and force them to engage in sexual activity.

The case was registered under Section 354-A (assaulting and stripping a woman of her clothes), Section 506 (criminal intimidation), Section 341 (punishment for wrongful restraint) and Section 509 (sexual harassment) of the Pakistan Penal Code.

"The video of violence against a woman and a man went viral on social media. Islamabad police immediately utilised all resources to arrest the accused in a few hours, registered an FIR and initiated legal action," Islamabad police said on Twitter.

Islamabad Deputy Commissioner Hamza Shafqaat said that the culprit had been arrested after police efforts. "His accomplices are also being arrested. It is once again requested to please delete the videos which show the victims," he said.

Hours later, the deputy commissioner said that all the suspects had been arrested.

The incident, which was highlighted on social media, quickly became the top trend in the country with netizens calling for strict punishment for the main accused, identified as Usman Mirza.

"Monsters like Usman Mirza are product of a culture in which they know they can commit horrific violence with impunity. Unfortunately, women face the brunt of our system's brutality," said activist Ammar Ali Jan.

Journalist Najia Ashar said just arresting the culprit was not enough. "Make an example out of this monster," she wrote.

PPP leader Naz Baloch said that instant justice and speedy trial of heinous offences is the only solution to root out violence against women.