A special police investigation into the deadly Itaewon crowd crush in October concluded Friday, with 23 officials referred to the prosecution, but with the Seoul mayor, safety minister and national police chief not among them.

Investigators referred officials, including the Mayor of Yongsan-gu Park Hee-Yeong, and the then-chief of the Yongsan Police Station, Lee Im-jae, to the prosecution on charges of professional negligence resulting in death.

Four other officials from the Yongsan Ward and the police were also referred to prosecutors for neglecting preventative measures.

Park Sung-min, former head of the Seoul Metropolitan Police Agency’s bureau of intelligence on public peace and security, and two high-ranking intelligence officers were arrested and referred for indictment on charges of deleting internal reports that warned of Halloween overcrowding.

Police also sought charges against the owners of the Hamilton Hotel for installing illegal structures in a narrow downhill adjacent to where the disaster occurred.

The probe team found Interior Minister Lee Sang-min, Seoul Mayor Oh Se-hoon and national police chief Yoon Hee-keun not legally accountable for the crowd crush.

The team formed of 501 personnel was launched by the National Police Agency in November to determine the causes behind the crowd crush and look into the response of related authorities. The special investigation team plans to officially disband by the end of this month after the disposition of seized materials.

The probe team concluded that the Itaewon tragedy was a “man-made” disaster caused by related authorities’ failure to devise preventative measures and quickly respond to an emergency.

The division also concluded that even after the disaster broke out adequate measures were not taken in accordance with manuals for handling disasters.

Further investigations regarding the Itaewon tragedy are being conducted by the prosecution, which will decide on whether to have those referred to stand trial.