Police have launched an investigation into a massive fire caused by a Mercedes-Benz electric vehicle at an underground parking lot of an apartment complex in Incheon on Aug. 1, while reviewing criminal charges against the management staff at the complex, officials said Sunday.

According to the Incheon Metropolitan Police Agency, they recently interviewed the first witness and the owner of the vehicle involved in the incident. The Mercedes owner reported that the vehicle had undergone routine maintenance last year and had been parked for three days before the fire, without any apparent issues. The initial fire report was made by a resident who entered the parking lot at approximately 6:15 a.m. to leave for work. This resident was the first to call emergency services, police noted.

The investigation heavily concentrates on a staff member from the apartment's management office, who allegedly deactivated the sprinkler system shortly after the fire alarm was triggered. According to the Incheon Fire Department's on-site investigation, at around 6:09 a.m. on Aug. 1, the property's control room received a fire alarm signal. The staff member then pressed the stop button for the sprinkler valve linkage, preventing the system from activating. By 6:14 a.m., when the button was released, the fire had already damaged the wiring, rendering the sprinklers inactive.

Fire authorities said on Aug. 9 that the failure of the sprinkler system, caused by its deactivation, likely worsened the fire damage. A key component of the investigation is determining whether charges of professional negligence resulting in injury will be filed against the staff member, according to police. Article 268 of the Criminal Act, which addresses death and injury by occupational or gross negligence, is the main legal provision for manslaughter in a corporate setting. It is punishable by up to five years in prison or a fine of up to 20 million won ($14,800).

In a bid to apply negligence charges against the staff member, authorities are assessing the injuries of 23 individuals: 20 who suffered from smoke inhalation, two who experienced dizziness and a firefighter who exhibited symptoms of a heat-related illness, police said.

In large buildings it is not uncommon for alarms to be temporarily deactivated due to false alarms, leading staff to manually override systems before confirming actual fires. A similar practice was noted in a 2019 incident, where a factory fire at the Namdong Industrial Complex in Incheon resulted in nine deaths after a guard manually silenced the alarm system. In that case, the guard was later sentenced to one year and four months in prison for professional negligence.

The National Forensic Service is to conduct a third analysis of the vehicle's battery pack Monday, which may uncover the ignition source.

In addition to the police investigation, the national fire agency is considering filing charges against the staff member for violating the Installation and Management of Firefighting Systems Act, which prohibits blocking or closing firefighting systems. Violations can lead to imprisonment of up to five years or a fine of up to 50 million won.

The Mercedes-Benz EQE electric vehicle exploded on Aug. 1 in the underground parking lot, with white smoke being seen before the explosion. The EV was not plugged into a charger at the time.