Investigators raided the offices of the Gwangju police chief and five other locations on July 11 as part of a probe into suspected collusion by the father of a murder suspect to destroy evidence.
The National Office of Investigation formed a special team to examine suspicions that a police officer in Gwangju colluded with colleagues to destroy evidence and access investigative information in his son's alleged murder of a high school student in May.
The lead investigator in the murder case was arrested earlier this week over concerns he might destroy evidence. Acting National Police Agency Commissioner Yoo Jae-seong cut short a trip to the United States and returned home on July 10. He apologized to the victim's family and the public while promising accountability.
The ruling Democratic Party demanded a full reinvestigation and said all individuals involved in destroying or omitting evidence should be targeted. The main opposition People Power Party said the prosecution's supplementary investigation helped expose issues in the case.
The prosecution has been conducting a parallel investigation into the police handling of the murder.
