Pakistan Prime Minister Imran Khan on Sunday promised “swift action” against those responsible for killing four people near Sahiwal city in an alleged encounter by the Counter Terrorism Department the previous day.

Police have claimed that one of the four, who was driving their car, was on the list of wanted terrorists, Dawn reported. He was reportedly the friend of the couple that was travelling in the car with their four minor children. The couple and one of their daughters were also killed. A son got a bullet injury.

“While the CTD [Counter Terrorism Department] has done a great job in fight against terrorism, everyone must be accountable before the law,” Khan tweeted. A joint investigation team has been appointed to investigate the incident and submit a report to the prime minister.

“As soon as the joint investigation team report comes, swift action will be taken,” Khan added. “The government’s priority is protection of all its citizens.”

Khan said he was shocked at “seeing the traumatised children who saw their parents shot before their eyes”. The prime minister said they would be now be looked after by the state.

The couple were identified as Mohammad Khalil, a grocer, and his wife Nabeela. Jalil, Khalil’s brother, had told the police on Saturday that the family was on their way to attend a wedding at the time of the incident, Dawn reported.

Family members of the deceased held an eight-hour protest in Sahiwal on Saturday against the killings, The Express Tribune reported. The victims’ family members placed their bodies on the Grand Trunk Road and organised a sit-in demonstration.

The demonstration ended after the Punjab Police registered a first information report against 16 personnel of the Counter Terrorism Department. The accused were taken into custody, and charges of murder and terrorism filed against them.

The Counter Terrorism Department had claimed that the operation was conducted based on inputs from an unidentified intelligence agency. It claimed that police officials had gestured to a car and a motorcycle to stop near the Sahiwal toll plaza, but the “terrorists” opened fire. In the subsequent shootout, four people were killed.

However, a new video has emerged showing there was no firing from inside the car in which the family was travelling. In the video, Counter Terrorism Department officials stop the car, take the children out of it and then fire at the vehicle.