Police have arrested three suspects over the alleged sexual assault, filming, and blackmail of a teenage boy in Pattoki city of Punjab's Kasur district, officials said on Tuesday.

The three suspects were nominated in a First Information Report (FIR) on Sunday and were arrested by a police team the next day.

Two others are also nominated in the police report. According to Kasur SP Investigation Mirza Abdul Quddoos Baig, police efforts are underway to arrest the remaining two suspects.

According to the FIR, registered on a complaint by the victim's father, the teenage boy had been "continually subjected to sodomy at gunpoint and blackmail by each of the five suspects over the past two-and-a-half years".

It is not clear whether the five suspects had any link with each other. According to police, the suspects would not extort money from the victim, as had been the case when a child pornography ring was unearthed four years ago in Kasur's Hussain Khanwala village.

The boy claimed that the suspects would film the act and would threaten him to comply with their requests or risk the footage being uploaded on social media.

According to police officials, one of the accused has also been named in a separate FIR filed on Monday by another complainant.

In the other FIR, the complainant has claimed that his brother was also subjected to sexual assault by the same suspect.

The suspect — a friend of the complainant — had lured the victim away under the guise of "going to a birthday party" three months ago, according to the police report.

The victim was then raped and threatened to keep quiet about the incident "for his own good".

After again being recently approached and blackmailed by the suspect, the victim finally informed his brother of the incident on Sunday and a complaint was then filed the next day.

The development comes days after the arrest of the suspected serial killer behind the murders of four minor boys in Kasur's Chunian tehsil.

Four children — aged between eight and 12 years — had gone missing since June this year with the latest, Faizan, 8, disappearing on the night of September 16.

The remains of three of them were found on September 17 from sand dunes near Chunian bypass.

In the last few years, Kasur has been rocked by multiple incidents of abuse, rape and killing of children. In January 2018, six-year-old Zainab Ansari was found dead in a trash heap near Shahbaz Khan Road, five days after she went missing. Hers was the 12th such incident to have occurred within a 10-kilometre radius in Kasur over a 12-month period. Her death had sparked nationwide protests and outrage.

The prime suspect, Imran Ali, had been arrested on January 23, 2018, and on June 12 the Supreme Court had turned down his appeal against the death sentence, noting that he had admitted to committing similar offences with eight other minor victims. Ali was subsequently executed in October last year.

In 2015, the district's Hussain Khanwala village had attracted worldwide attention when a child pornography ring was busted. Hundreds of video clips had emerged showing a gang forcing dozens of minor boys and girls to perform sexual acts and filming them. The gang had also used the videos to blackmail families of the children and extort millions in cash and jewellery from them.