The 25-year-old Sikh youth Ravinder Singh from the remote Shangla district of Khyber-Pakhtunkhwa, was found dead in Peshawar on Sunday.
Ravinder Singh, said to be the brother of a Sikh journalist Harmeet Singh, lived in Malaysia and had returned home for his wedding.
A senior security official told The Express Tribune on Thursday that it was a "contract killing" paid for by Ravinder's fiancee, Prem Kumari, who didn't want to marry him.
She promised the hitmen Rs 7,00,000 (Pakistani currency) for Ravinder's murder, the official added.
"Part of the committed money was paid in advance, while the rest had to be paid after the murder."
According to the investigation team, Ravinder was murdered in Mardan and later his body was shifted to Peshawar by the hitmen. Prem Kumari has been taken into custody at Mardan, one investigator said.
"In Peshawar, the hitmen dumped the body at a deserted place and called the family from Ravinder's phone to demand ransom or else they would kill him," he added. "All this was done to divert any investigations into the murder."
Ravinder's body was found dumped at a deserted place in the precincts of Chamkani police station on Sunday - a day after he was murdered.
The investigation team - led by Peshawar's capital city police officer - cracked the blind murder case after four days of arduous investigations in which officials from other investigative and intelligence agencies also provided valuable clues.
"The Hindu nationalist government of Narendra Modi tried to portray it as a religiously motivated 'target killing' to malign Pakistan for alleged persecution of religious minorities - triggering an angry rebuke from Islamabad," the media said.
"Indian attempts to politicise the tragic killing of [the] Pakistani Sikh youth are mischievous and reprehensible," the Pakistani Foreign Office spokesperson said on Monday.
"As this crime was reported, a case was registered immediately and a high-powered committee constituted to investigate the matter. The law will take its course and those responsible will be brought to justice," she added.
"Rather than feigning any dishonest concern for minorities elsewhere, the BJP government would do better by focusing on the ongoing human tragedy at home and protecting India's minorities from 'Saffron terror'," she said.
A day later, Indian Charge d'Affaires Gaurav Ahluwalia was summoned to the Foreign Office to convey "Pakistan's strong rejection of baseless and fabricated" allegations of mistreatment of the Sikh minority community in the country.
( With inputs from IANS )