A day after three members of a family were allegedly killed during a shootout between the Counter-Terrorism Department and suspected terrorists near Sahiwal, Prime Minister Imran Khan promised that "swift action" would be taken against those found responsible for wrongdoing.

In what law enforcers described as an encounter with terrorists, the elite Punjab police on Saturday killed four people, including parents and their teenage daughter, sending shock waves across the country as one of the three surviving children who were witness to the episode denied the official version in a video that went viral on social media.

Prime Minister Khan took to Twitter on Sunday to recognise the CTD's "great job in [the] fight against terrorism", but stated that "everyone must be accountable before the law".

"As soon as the joint investigation team report comes, swift action will be taken," he vowed. "The government's priority is protection of all its citizens."

He added: "Still shocked at seeing the traumatised children who saw their parents shot before their eyes. Any parent would be shocked as they would think of their own children in such a traumatic situation. These children will now be fully looked after by the state as its responsibility."

Sahiwal protest ends after FIR registered

Relatives of the victims, who held an over eight-hour-long sit-in protest in Sahiwal against the killings ─ along with the bodies of the deceased ─ ended the sit-in after a first information report was registered against unidentified CTD officials for the 'encounter' killings at the Yousufwala police station.

The FIR ─ which was filed on the complaint of the brother of deceased Khalil, Jalil ─ said that Khalil, a grocer in Lahore, left for Burewala with his family ─ wife Nabeela and four children ─ and friend Zeeshan to attend a wedding.

It said when they reached the tollplaza in Qadirabad, an Elite Force vehicle came up behind them. It alleged that the 'encounter' was premeditated and spread fear and panic in the area, and that action should be taken against those responsible.

Jalil had, while speaking to DawnNewsTV earlier, said that the police, instead of filing a case against the killing of his family members, filed an FIR containing sections pertaining to terrorism against the deceased.

He added: "They aren't filing an FIR for us," he had claimed, adding: "They said it must be filed in Lahore, but the incident happened in Sahiwal, so how can we file an FIR in Lahore?"

Read more: Victims’ relatives, neighbours in Lahore vent their spleen against CTD

"We will not remove their bodies [from the road] unless we get justice," he had asserted. "Whether it takes 10 days, 15 days, 20 days, a month or two months."

"Chief Minister Usman Buzdar's hospital visit was just eyewash. We are not satisfied with the steps taken," Jalil added.

CM Buzdar had ordered the arrest of the CTD officials involved in the 'encounter'. An unknown number of CTD personnel were taken into custody following his directives.

After the FIR was filed, the protesters ended their sit-in and the road was re-opened for traffic.

Relatives and residents are protesting in Lahore against the killing of the "innocent and unarmed civilians" by the CTD. The metro bus service has been suspended and Ferozepur Road has been closed to traffic due to the protest.

According to the protesters, the sit-in will continue until justice is served.

Sahiwal 'encounter'

Khalil, a resident of Kot Lakhpat, Lahore, his wife Nabeela, their 13-year-old daughter, and their neighbour, Zeeshan, were on their way to a wedding in Burewala when they were killed in firing on their car near the toll plaza on GT Road in the Qadirabad area.

Three children in the car survived. Khalil and Nabeela's minor son sustained a bullet injury while their two other daughters remained unhurt.

According to an initial medical examination, Khalil sustained 13 bullet wounds in his chest and head, his wife Nabeela sustained four, Zeeshan was found to have 10 bullet injuries; and Areeba, six bullets, hospital sources told DawnNewsTV.

CTD officials said those killed in the shooting were terrorists belonging to a proscribed militant organisation, Daesh. The CTD spokesperson identified one of them, Zeeshan, as an active member of the banned outfit, explaining that the terrorists used to travel with families to avoid police checking.

The CTD Sahiwal team was conducting a joint Intelligence-Based Operation on the basis of information from the CTD and a sensitive agency, the spokesperson said, adding that they had to retaliate when they came under fire from those in the car.

As the news flashed on TV screens, scores of relatives of the deceased family took to the streets, blocking traffic on the Lahore-Kasur road to protest the murder.

To ascertain facts, the prime minister ordered an immediate inquiry into the matter.

Later on Saturday evening, Punjab Chief Minister Usman Buzdar directed Inspector General of Punjab Police Amjad Javed Saleemi to ensure arrest of all the personnel involved in the killing of the four persons.

A Joint Investigation Team (JIT) was also constituted under the supervision of Additional IG Police Syed Ijaz Shah to investigate the incident.

Varying explanations from CTD

Varying versions put forward at different stages following the incident cast doubts over the CTD explanation.

The news broke when the CTD told the media that four suspects were killed in an encounter at the Sahiwal toll plaza near Qadirabad on Lahore-Multan motorway at noon. The officials initially described the shooting as a daring attempt of the law enforcers to rescue a group of kidnapped children from their captors.

However, it was soon replaced by another explanation by the officials who said some dangerous terrorists with links to Daesh were travelling in the car which was intercepted by the police near the toll plaza.

The CTD officials said Zeeshan was an active member of the banned organisation. "It was in continuation of the operation conducted in Faisalabad on January 16," said the CTD spokesperson. He said the CTD was tracking the remaining Daesh-linked terrorists in the Red Book, namely Shahid Jabbar and Abdul Rehman.

On Saturday morning, he added, intelligence information was received that they were travelling towards Sahiwal with arms and explosives.

"Today, they were warned to surrender but they started firing," he had said, adding that the terrorists namely Shahid Jabbar, Abdul Rehman and their unidentified accomplice fled the scene on a motorcycle while resorting to firing.

Surviving child's account

The situation took a new twist when the injured minor son of the deceased parents narrated the firing incident in a video that flashed on television screens in the afternoon. It was actually an amateur video ─ one of probably many ─ that made it impossible for anyone to conceal facts about the deadly shooting.

The young boy’s was a horrific account that lent credence to the talk about it being possibly a case of mistaken identity.

He said the family was fired upon out of nowhere as they were travelling to Burewala from Lahore to attend the wedding of a paternal uncle of his.

“My father told them to take the money but spare us,” he said, but the plea had little effect on the law enforcers.

The child denied that there were any weapons in the car, and spoke of how he and his two younger sisters were temporarily left by the police at a petrol station, some kilometres from the crime scene, after the firing. The law enforcers returned some time later to take the three children to a nearby hospital.

Some witnesses quoted widely by TV channels corroborated the assertion that there had been no firing from those travelling in the ill-fated car. One witness said the elite police forced the vehicle to stop and fired at the car occupants from a close range.