A fire that broke out in an apartment building in Dobong-gu, northern Seoul that left two people dead and injured 30 others Monday was likely caused by human negligence, the police and fire authorities said Tuesday.

A police official on-site said that it seems “unlikely that the fire was ignited due to electrical factors” after a joint on-site investigation.

“It seems unlikely that the fire was caused by a short circuit or malfunctioning electrical equipment. Based on the evidence that has been obtained, it is highly likely that the fire was human-caused,” said the police official.

Twenty-one personnel from the local police department, local fire department and Korea Electrical Safety Corporation were involved in a joint forensic investigation to look into the cause of the fire from 11 a.m. Tuesday.

The investigators focused on a room in a third floor apartment that is believed to be the ignition point and the details behind the accident.

The police stated that it is difficult to comment on specific details behind what caused the fire, such as conclusive evidence that the police found or statements made by those involved. However, all other factors that could have contributed to the fire have been ruled out.

According to the police, there were no abnormalities found in the fire alarms installed in the apartment building at the time of the incident. However, the police stated that it is likely the fire spread quickly, as the fire-resistant doors on all floors were left open.

Another factor that investigators believe likely caused the fire to spread quickly was the fact that the apartment’s first floor was built in using pilotis -- supports like pillars or columns that lift a building above the ground. Large-scale fires frequently occur in piloti-type buildings, as insulation materials in the ceiling are ignited and air can easily come in from outside.

It was additionally found that sprinklers were only installed from the 16th floor and above, which is believed to have also contributed to the damages. Currently, the law requires sprinklers to be installed on all floors of apartments that have more than six floors.

Meanwhile, according to the fire authorities, officials were notified about the fire occurring on the third floor of the 23-story apartment building at around 4:57 a.m. on Monday. Local fire department officials mobilized 60 vehicles and 312 personnel and fully contained the fire at 8:40 a.m., around four hours after the initial report was made.

Two men in their 30s were reported dead in the fire, and 30 others were sent to the hospital due to injuries. Out of the 30, three are believed to be in critical condition.

One of the fatalities died after jumping from the fourth floor of the building carrying his child, in a desperate attempt to flee. Another fatality was a 38-year-old individual identified by his surname Lim. Lim, a resident of the 10th floor, was discovered in full cardiac arrest on the stairs of the 11th floor.