Police said Saturday that they have been investigating the organizers of a pop concert held the previous day where the collapse of a ventilation grate killed 16 people and injured 11 others.

   The tragic accident took place Friday at Pangyo Techno Valley, a multipurpose complex for technology, just southeast of Seoul, as a grate over a ventilation shaft gave way due to the weight of the victims who stood on top of it to get a better view of the open-air pop concert. The victims fell four stories to the basement of a parking lot due to the accident.

   Police said that they have called in organizers and sponsors of the concert to determine the exact cause of the accident.

   "As a loss of lives occurred, we plan to investigate whether the host abided by security measures," a police officer said. "If violations of safety rules are found, we will take actions to punish those responsible for the accident."

   Some 700 people attended the concert where various South Korean musicians, including girl group 4Minute, performed, according to the host.

   Meanwhile, an official dealing with safety measures for the concert was found dead earlier in the day in an apparent suicide, according to police.

   The 37-year-old man, only identified by his surname Oh, was found dead on a street nearby the building of his office, located in Pangyo Techno Valley.

   A suicide note was not found, but he reportedly left a short message on his social network account that reads "I apologize to the victims. I'm sorry to my family."

   Footage from closed-circuit TVs showed Oh climbing up to the rooftop of the building using emergency stairs. According to the police, he then likely jumped to his death. Earlier in the day, he underwent a police probe before returning to his office, according to the police.

   Oh was known to have written a document related to safety measures at the Gyeonggi Institute of Science and Technology Promotion.

   The institute was one of the sponsors of the event, whose main organizer was local business new provider Edaily.

   The deadly collapse comes six months after the sinking of the ferry Sewol, which killed more than 300 people, mostly high school students on a school excursion. (Yonhap)