The remains of the young Korean worker beheaded by Iraqi militants last week were returned to South Korea Saturday, as South Korean officials formally announced an investigation into the government's alleged mishandling of the case. A military honor guard received Kim Sun-il's body at the airport in Seoul, while grieving relatives waited to escort it home for burial.

The young man's murder in Iraq has gripped the nation, and amplified public anger over the government's decision to send troops to support the U.S.-led coalition in Iraq. Hundreds of demonstrators in Seoul staged a rally Saturday for a third night, calling for the scheduled troop deployment to be canceled.

Hours earlier, opposition parties in Parliament announced that they would launch an investigation into the government's handling of the kidnapping case.

President Roh Moo-hyun had already ordered his own inquiry, to counter charges that his administration intentionally delayed word of Mr. Kim's kidnapping for nearly three weeks.

Political scientist Jaung Hoon of Chung An University in Seoul says the allegations highlight widespread frustration with President Roh's management style.

"The people are getting tired of the inability or the lack of capacity of the government to deal with crisis cases and lack of information and lack of coordination among government ministries," he said.

The government insisted it first learned of the kidnapping on June 21, when the Arab media showed a video of Kim in captivity. After repeated denials, the Foreign Ministry confirmed Friday that it had heard of a possible kidnapping from The Associated Press on June 3, but failed to pursue the lead.

The controversy is a serious problem for President Roh, who last month defeated an attempt to impeach him. Professor Hoon says the matter could cause second thoughts among the president's advisors about sending troops to Iraq.

"The issue will snowball into a major political crisis for the president," said prof. Hoon. "There will be a serious challenge from his own side, from his own party, and from his own supporters, so it's a big challenge for the president."

South Korea currently has 6,070 troops in Northern Iraq, and has made a commitment to send 3,000 more in August.