The Democratic Party(DP)-led opposition on Thursday passed a bill mandating a special counsel investigation into a controversial military report regarding a Marine's death last year.

Of the 190 lawmakers present, 189 voted in favor of the bill, while one opposed, as members of the ruling People Power Party(PPP) boycotted the proceedings in protest.

In an attempt to block the bill, PPP lawmakers the previous day started a filibuster and continued the relay speeches for over 24 hours until Thursday afternoon. 

Speaker Woo Won-shik, however, put the brakes on the speeches, invoking related provisions in the National Assembly Act that allows forcing an end to a filibuster after 24 hours when three-fifths of parliament members consent to it.

The bill seeks to appoint an independent counsel to get to the bottom of allegations that the Yoon Suk Yeol administration interfered in the military's report.

While searching for missing victims of last year’s heavy rain, Marine Corporal Chae Su-geun was swept away by a torrent, and was later found dead. His death sparked anger nationwide for the Marine Corps’ unsafe search and rescue operation.  

The opposition argues that then defense minister Lee Jong-sup and presidential officials wielded undue influence and hindered a fair investigation into the 20-year old soldier’s death. The opposition also suspects President Yoon exerted pressure on them to protect the top brass in the Marine Corps. 

Almost a year after Chae’s death, main opposition Democratic Party lawmakers started to discuss the possibility of a presidential impeachment, claiming that abuse of power can form grounds for impeachment.

PPP lawmakers accused the opposition bloc of pushing the bill to try and impeach President Yoon Suk Yeol.

President Yoon in May vetoed a similar bill pushed by members of the previous 21st National Assembly, but the newly-elected members of the opposition-dominated parliament pushed for a special counsel probe soon after they began their duties at the end of the same month.