The case illustrated India's appalling record on violence against women and children and drew criticism of the ruling far-right Hindu nationalist Bharatiya Janata Party (BJP) after members hold rallies in favor of the accused and protested their arrest.
Of eight people accused in the girl's case, including a former government official, four policemen, and a minor, one man identified only as Vishal was to be freed after being found not guilty, defense lawyers said. The last, a juvenile, awaits trial.
"This is a victory of truth," said prosecution lawyer M Farooqi after the convictions. "The girl and her family have got justice today."
The girl, from a nomadic Muslim community that roams the forests of Indian-occupied Kashmir, was drugged, held captive in a temple and sexually assaulted for a week before being strangled and battered to death with a stone. Her battered body was discovered three weeks later.
According to the charge sheet, she was "raped for days, tortured and then finally murdered.”
The prosecution had sought the death penalty for the three men - including a Hindu priest - who received life sentences.
Three other men, all police officers, received five-year terms for destroying evidence. The abduction, rape, and killing of the child was part of a plan to remove the minority community from the area, the 15-page charge sheet said. It was fuelled by religious hatred as former Hindu government official Sanji Ram had expressed hateful speech against the Muslim nomadic tribe.
In a 432-page judgment, the court also levied fines of 150,000 rupees (US$2,150) on the three men given life terms - priest Sanji Ram, Deepak Khajuria and Parvesh Kumar.
The policemen - Surinder Kumar, Tilak Raj, and Anand Dutta - were also fined 50,000 rupees (US$718) each.
Defense lawyer Vikram Mahajan said all six would appeal.
The father of the victim said that he expected capital punishment. "They should have been dealt the same way as they murdered my daughter. How could they acquit one accused in the crime? That’s injustice," he said.
The trial began in Kathua in Jammu and Kashmir state more than a year ago, but India's Supreme Court shifted it to Pathankot in neighboring Punjab state after the girl's family and lawyer said they faced death threats.
Lawyers and Hindu politicians, including some from the ruling BJP, had also held protests against the charges.