The arrest and trial of US diplomat Col Joseph Emanuel Hall, who ran over a biker in Islamabad, was not possible as he enjoyed diplomatic immunity, said Inspector General (IG) Islamabad, Sultan Azam Temuri on Tuesday.

Speaking to a private television channel, the Islamabad IG said that the American military attaché's case would be heard by the American judiciary. He said that a challan was submitted in court on the criminal case against Col Joseph and relatives of the deceased would appear before the court.

"In case an agreement is not reached with relatives of the deceased, a letter will be written to the foreign ministry to summon Col Joseph," he said.

The US military attaché was at first barred from leaving the country but later his name was removed from the blacklist. A few hours later, Col Joseph left Pakistan for the USA.

The accident and Ateeq Baig's death sparked protests in Islamabad as members of the civil society called on authorities to hold the US military attaché accountable.

A CCTV footage showed the American diplomat broke a traffic signal. His car went on to collide with the motorcyclist.