Story highlights The official handled safety at a concert, where an accident killed 16 on Friday

A ventilation shaft gave way, dropping more than two dozen concert goers four stories

The man was found dead on Saturday

He posted a message to Facebook apologizing to the victims and his family

A day after 16 died in an accident at a concert in South Korea , a man responsible for safety measures was found also dead, the country's semi-official news agency reported. It was an apparent suicide.

On Friday, a ventilation grate gave way, and more than two dozen people standing on it plunged some 20 meters (66 feet) -- or four stories -- into an underground parking structure below, a government accident response task force said.

In addition to the deaths, eleven people were injured, three seriously.

On Saturday, the body of the 37-year-old safety official was found on a street near his office, Yonhap news agency reported, citing police. They think he jumped to his death.

He left a brief message on his Facebook page. "I apologize to the victims. I'm sorry to my family."

On Friday, Prime Minister Chung Hong-won inspected the gaping concrete hole that swallowed up concertgoers.

Some media reports indicate the victims were standing on the grate in order to get a better view of the stage.

A witness told CNN affiliate YTN, "There was a sudden, loud screaming and when I turned, it looked as if people were being sucked down into a hole."

About 700 people were attending the concert, which featured South Korean artists, including the popular all-female group 4Minute, Yonhap reported.

A ferry sinking in April killed more than 300 people, many of them schoolchildren, and caused nationwide outrage.

Critics contend safety measures and regulation are not keeping pace with the fast-paced economic development in the country.