MANILA, Philippines?Since 1998, there have been more than 800 victims of unexplained killings in Davao City. Because most of the victims had criminal records, the murders were blamed on a vigilante group, known as the Davao Death Squad (DDS).

In the late 1990s, the killers rode on motorcycles and gunned down their victims, most of whom were known to be gang members and illegal drug peddlers. In recent years, the killings were done by stabbing.

Some victims were murdered just minutes after their release from prison, while others were executed days after a crime had been committed.

In some cases, the DDS warned families of would-be victims.

The DDS killed 814 persons, 73 of whom were minors, from 1998 to mid-February of this year, according to the Coalition against Summary Execution.

Only one case of summary execution has been filed in court since 1998, said Isaac Robillo, executive judge of the Regional Trial Court of Davao.

That the murderers appeared to move with impunity led some to accuse tough-talking Mayor Rodrigo Duterte of Davao City of being behind the DDS.

Duterte was Davao City congressman when the killings started in 1998. He was elected mayor in 2001 and reelected to the post in 2004 and 2007.

He has been quoted as saying: ?If you are doing an illegal activity in my city, if you are a criminal or part of a syndicate that preys on the innocent people of the city, for as long as I am the mayor, you are a legitimate target of assassination.?

But Duterte denied that a death squad was operating in the city, and blamed the killings on gang wars, rivalries in the illegal drugs trade and personal grudges.

Alarmed by the wave of killings and the public?s seeming acceptance of it, the Commission on Human Rights (CHR) opened a two-day public inquiry on March 30.

During the inquiry, Duterte promised to resign as mayor if any evidence was presented to prove the existence of the DDS and that he was involved in the murders.

On March 31, he gave up control of the city?s police forces and severed his ties with Task Force Davao, a military unit formed to protect Davao City from terrorists, ?to give the [CHR] a free hand and unhampered conduct of its ongoing investigation ??

In April, CHR Chair Leila de Lima said former hit men of the DDS had linked some government officials to the shadowy group. Inquirer Research; Sources: Inquirer Archives, Davao City website