One of the suspects arrested for the murder of Singapore-based model Fehmina Uzair Chaudhry is the son of a diplomat who was based in Singapore until a few months ago, Pakistan police said.
The family of Muaz Waqar, 24, insisted he had been tortured into confessing to the crime.
The police, who arrested a second man last month, said the trial will start soon.
"Muaz is the son of Samina Waqar, who served in the Pakistan embassy in Singapore," police investigator Javed Awan told The Straits Times.
Waqar, who studied for three years in Singapore, admitted to the murder last month, the police said.
The second suspect, identified as Asif Mehmood Abbasi, was arrested on Oct 22.
Mr Awan said Abbasi confessed to strangling the 27-year-old woman with a rope. Abbasi, believed to be in his 20s, worked as an office assistant for Waqar, a real estate agent, said Mr Awan.
According to local media reports, Waqar became friends with Ms Chaudhry in Singapore and they wanted to start an advertising and fashion business in Pakistan. He was also helping to negotiate land deals for her.
Ms Chaudhry reportedly gave him gold jewellery worth three million Pakistani rupees (S$35,000) to buy land but when the deal fell through, she asked for her money back.
Waqar then offered her a modelling deal.
On Oct 10, Ms Chaudhry and the two men went to meet some people about a land deal. She went missing after that.
Police said telephone records showed contact between her and Waqar. Photographs of them are also found on his Facebook page.
But Waqar's family, who returned to Pakistan from Singapore in June, denied he was friends with the model or that he is a real estate agent. When Waqar was in Singapore, he studied for an MBA in project management and human resources, and also studied at the Association of Chartered Certified Accountants, a family member said.
"He never confessed anything to police. He is being tortured, the police are applying third-degree torture tactics to force him to confess to a crime he never committed," the family member told The Straits Times on condition of anonymity.
Waqar's family claimed Abbasi and another man were involved in the murder, and that the man fled to Saudi Arabia.
"Muaz is a 24-year-old boy. He has not committed any crime. He is not a real estate agent," the family member said. "Our lawyers have stopped us from saying anything in public but we will reveal everything once the trial starts."
Ms Chaudhry's body was found in a drain on Oct 14, two days after her mother Nashiba Taskeen reported her missing.
In her police report, Ms Taskeen said her daughter contacted her on Oct 9 to give her hotel details after going to Islamabad from Karachi to meet Waqar.
The last time they spoke to each other was on Oct 10, after which Ms Taskeen received a text message saying her daughter had been kidnapped.
Police traced the message to Waqar and arrested him. He said he killed Ms Chaudhry, Mr Awan said. He then led police to the place her body was dumped.
It is believed Ms Chaudhry moved to Singapore with her husband a few years ago, but they divorced last year. The couple have two children.