The 16-year-old girl was set on fire last week in the town of Donga Gali, about 50 km (30 miles) northeast of the capital, Islamabad, on the orders of the council, said district police chief Saeed Wazir.
Police said the honour killing was ordered as punishment for what the council deemed irreparable damage to the village's reputation. The couple appeared to have escaped.
The girl's mother and brother were also arrested, Wazir said, as they were present during the meeting and allegedly agreed to the sentence.
Jirgas, or tribal councils, are often called in Pakistan's northwestern regions as a means of local conflict resolution, but their edicts have no legal standing under Pakistani law.
The girl's mother told police her daughter had helped a couple from the nearby village of Makol elope, in defiance of cultural norms.
"The jirga then took her to an abandoned place outside the village and made her unconscious by injecting her with some drugs," said Wazir.
"Then they seated the girl in a van in which the couple had escaped. They tied her hands to the seats and then poured petrol on her and the vehicle."
The vehicle was set ablaze.
"I hadn't seen such a barbaric attack in my whole life," he said.
More than 500 men and women were killed in honour killings in Pakistan last year, according to the Human Rights Commission of Pakistan. Many of those crimes are carried out by relatives who say the victims have brought shame on the family.
Few cases go to court, but among those that do, attackers are often forgiven under a clause of law rooted in Islamic law. Legislation is currently pending at Pakistan's parliament to close the loophole, which many say encourages such attacks.
Posted by Women Against Shariah on Sunday, May 8, 2016