All five victims who died in a fire in a soundproof tunnel on a highway in Gwacheon, Gyeonggi Province, Thursday, were identified Saturday.

“The identity of the five victims has been confirmed through DNA tests by the National Forensic Service,” the Gyeonggi Nambu Provincial Police Agency said Saturday.

The forensic service confirmed that, of the five victims, three were women and two were men. Three were in their 60s, while the others were in their 20s and 30s, respectively.

Two women, who were mother and daughter, were found in the same vehicle and the other three were found in three different vehicles.

The NFS has also conducted autopsies on victims to determine the exact cause of death, but it will take more time for the results to come out.

The police are continuing the probe to figure out the cause of the fire. They have booked the truck driver on a charge of professional negligence and have questioned him twice.

Police conducted a search and seizure operation Saturday on the waste collecting company to which the truck assumed to be the initial point of ignition belonged. The authorities are reportedly considering the possibility that inadequate maintenance or outdated components caused the fire.

The fire was first reported at 1:49 p.m. on Thursday, immediately after a truck passing through a soundproof tunnel installed on the Second Gyeongin Expressway near North Uiwang Interchange caught fire. The fire spread rapidly to the plastic walls of the soundproof tunnel.

The fire burned a 600-meter section of the 830-meter-long tunnel until it was completely extinguished at 4:12 p.m., leaving five dead and 41 injured.