JAKARTA – Indonesia's top graft-buster was named a suspect and a mastermind in a murder case on Friday by the attorney-general's office, dealing a blow to the agency and possibly to President Susilo Bambang Yudhoyono's re-election chances.

Antasari Azhar, the 56-year-old head of the Corruption Eradication Commission or KPK, is one of several suspects in the murder of Nasrudin Zulkarnaen -- a businessman who, according to local media reports, had been a witness in a corruption case investigated by the agency.

In the case of the premeditated murder of Nasrudin Zulkarnaen in Tangerang area on March 14, 2009, one of the suspects and masterminds is Antasari Azhar, Jasman Panjaitan, a spokesman for the AGO, told a news conference.

Zulkarnaen, a director of state-owned pharmaceutical firm Putra Rajawali Banjaran, was shot by two gunman after he had finished playing golf in Tangerang, a town west of Jakarta, according to local media reports.

Azhar could not be reached for comment, but late on Thursday, he told reporters he was not involved in the case, local media reported.

The KPK has been at the forefront of President Yudhoyono's campaign to crack down on corruption, and several high profile politicians, central bankers, and officials -- including some from the attorney-general's office -- have been charged and imprisoned as a result of its investigations.

President Yudhoyono, a reform-minded ex-general who is seeking re-election in presidential elections in July, has pushed for a crackdown on corruption using the KPK, which started operations in 2003, and an independent corruption court.

Earlier on Friday, a senior immigration official said that the attorney-general's office had requested a travel ban to prevent Azhar from leaving the country.

The Jakarta Post quoted National Police Chief Gen. Bambang Hendarso Danuri as saying the police had arrested nine suspects in the murder and that the investigation had led us to the mastermind, who is a well-known businessman.

In an interview with Reuters last year, Azhar said he expected the agency to be kept busy for at least the next five to 10 years, creating a climate of fear in a bid to keep public officials honest.

Indonesia regularly ranks among the most corrupt countries in the world, a factor that deters foreign investment and hampers its economic growth.