A joint police and prosecution team was set on Thursday to question four more election officials over ballot shortages that disrupted the June 3 local elections.
The team plans to question the officials about the National Election Commission's response measures. The shortages temporarily suspended voting at 26 polling stations nationwide.
Investigators are probing allegations that the commission hastily reduced the number of printed ballots and failed to respond effectively on election day. The questioning follows a raid a day earlier on the offices of 12 election commission officials in Seoul.
Meanwhile, protesters demanding a rerun of the elections continued to rally outside the Olympic Park Handball Stadium in southern Seoul for the 21st day.