ALMATY, Kazakhstan (AP) _ Kazakhstan's intelligence agency said Tuesday that five of its employees were among the six arrested suspects in the murder of an opposition leader.

The National Security Committee statement comes amid opposition allegations of government involvement in the Feb. 11 murder of Altynbek Sarsenbayev, a leader of the Nagyz Ak Zhol party.

He was the second prominent government critic to be killed in the oil-rich Central Asian nation in the past three months.

Sarsenbayev was kidnapped along with his bodyguard and driver, and all three were shot dead in mountains near the commercial capital Almaty.

Interior Minister Baurzhan Mukhamedjanov said Monday that police had arrested a man suspected of ordering the murder along with five suspected killers. He said the detainees had confessed to the murder.

``Five servicemen of the National Security Committee's Arystan group have been arrested on suspicion of involvement in this crime,'' the security service said in a statement Tuesday.

Arystan, or Tiger, is the security agency's elite division used for anti-terror and other special operations.

The security committee also said in the statement that it was working ``to find all real participants in the murder and reveal werewolves among its ranks and punish those who allowed this to happen.''

Interior Minister Mukhamedjanov has said that the alleged organizer ordered the killers to kidnap ``some businessman'' for $25,000. Sarsenbayev was not known to be involved in business activity.

The opposition has said the murder was political and was carried out by the special services.

The investigation is being assisted by an FBI agent invited by the authorities.

Zharmakhan Tuyakbai, leader of the For a Fair Kazakhstan opposition alliance and former chief prosecutor, said Tuesday that he had information that the sixth arrested suspect was a former law-enforcement officer.

``The question today is whether the law-enforcement agencies have the will to solve this crime and find all those behind it,'' Tuyakbai told The Associated Press.

``It all comes from the impunity with which law-enforcement agencies were allowed to act ahead of the elections, harassing and intimidating the opposition,'' he said, referring to the December presidential vote in which President Nursultan Nazarbayev earned a new term.

The vote was criticized by Western observers as flawed.

Nazarbayev, who has ruled the ex-Soviet republic for 16 years, has been criticized in recent years for growing authoritarianism.

Sarsenbayev, a 43-year-old former government minister and ambassador to Russia, joined the opposition in 2003.

Three months ago Zamanabek Nurkadilov, an outspoken critic of the president and a former regional governor and emergencies minister, died from multiple gunshot wounds. Authorities ruled the death a suicide.