Kuala Lumpur traffic investigation and enforcement department chief Zamzuri Isa said the driver will be released from police custody tomorrow, while their investigation paper will be submitted to the deputy public prosecutor at about 8.30am.

However, he said police are still looking for more witnesses to assist in the investigation.

Zamzuri said the pillion rider is being treated in intensive care.

A viral video showed the four-wheel-drive vehicle – a Nissan Navara – hitting the motorcycle as it tried to overtake it on the left lane of the highway, throwing the 53-year-old motorcyclist and his 49-year-old wife onto the road.

The motorcyclist sustained a fractured collarbone and injuries to his ankle, while his wife suffered more serious injuries, including bleeding from the head, a fractured ankle and a broken right rib.

The driver, 32, had fled the scene before he filed a police report more than four hours later. He told police he left for fear he would be confronted by other road users.