A separatist politician whose mutilated body was found in Pakistan's restive southwest had helped secure the release of a kidnapped American UN worker, the US Embassy said. The remains of Ghulam Mohammed Baloch and two others were discovered in Baluchistan province on Thursday, six days after they were reportedly abducted by armed men. The deaths sparked rioting across the region, where ethnic Baluch groups have waged a long and often violent struggle for greater autonomy or outright independence that apparently included the kidnapping of the American. Baloch played “an active role” in seeking the release of John Solecki, the UN refugee agency staffer released unharmed last weekend, the US Embassy said. The American government condemned the killings and urged Pakistani authorities to bring those responsible to justice, the embassy said in a statement late Thursday. The UN also expressed “serious concern” about the killing. Provincial officials have pledged a full investigation. Rights groups accuse Pakistani security forces of abducting scores of Baluch activists and secretly holding them in a bid to crush the yearslong movement. Several leaders have been killed. Gunmen abducted Solecki in the regional capital, Quetta, in February and threatened to kill him unless authorities freed hundreds of people allegedly held in Pakistani jails. The government said it had “traced” some 200 missing persons, but it remains unclear if any were released to secure Solecki's freedom. A UN statement said all three slain Baluch leaders were involved with a committee set up by the provincial government to investigate disappearances. It urged the government to ensure the committee continued its ´important work.