The man they call Dirty Harry

In the Philippines and beyond, the southern island of Mindanao is a byword for civil war, anarchy and violence. Its mountains and jungles harbour separatist guerrillas locked in a struggle for an independent Muslim state. Kidnappings are rife, and a Communist insurgency has raged for decades. Tribal warlords backed by private militias rule a fearful population at gunpoint.

In the Philippines and beyond, the southern island of Mindanao is a byword for civil war, anarchy and violence. Its mountains and jungles harbour separatist guerrillas locked in a struggle for an independent Muslim state. Kidnappings are rife, and a Communist insurgency has raged for decades. Tribal warlords backed by private militias rule a fearful population at gunpoint.

The exception is Davao, a bustling metropolis on the south coast of Mindanao, nestling at the foot of Mount Apo, the country's highest peak. Under the leadership of its mayor, Rodrigo Duterte, the rate of street crime in the sprawling port city has plummeted. Davao, voted one of Asia's "most liveable" cities by Asiaweek magazine, is booming. Foreign investment is flooding in.

But Davao's reputation as an oasis of law and order in one of the world's most dangerous regions masks a dark secret. Since Duterte took office three years ago, the city has witnessed a wave of murders, carried out in daylight by assassins on motorbikes. The victims are young men and street children suspected of petty crime. The death toll has reached 241, and not a single person has been arrested.

This is one statistic that proud civic authorities are not so keen to trumpet to the outside world. For the killings are believed to be the work of a shadowy vigilante group, the Davao Death Squad, which reportedly operates with the blessing of the police and City Hall. In fact, it is difficult to find anyone in Davao who is not convinced that the squad was created by Duterte himself.

The mayor, who has acquired nationwide notoriety as the "Dirty Harry of the Philippines", denies that the murders are officially sanctioned. But he recently boasted on the campaign trail that the number of killings - more than 100 last year - would double if he was re-elected this week. "Let me tell you a secret," says a taxi driver, in a conspiratorial whisper. "He is mayor by day and terminator by night. They should rename him Arnie Schwarzenegger."

Bizarre though it seems, few people in this city of 1.2 million are disturbed by the sight of dead bodies turning up, almost daily, on the streets. They call it the "40-pesos solution" to crime, referring to the cost of a bullet, about 40p. "I like it," says Davao's tourism officer, Edmundo Acaylar, stuffing a handful of cashew nuts into his mouth as he waits impatiently for dinner. "Whoever is doing it, I say 'thanks very much, you're doing a great job'. They are ridding Davao of criminals and making it a safe place. I call it a process of expurgation."

Most of the victims come from the city's slum communities, where half a million people live in grinding poverty. Many are teenagers, some as young as 14, whose only "crime" was sniffing solvents - said to take away hunger pangs. Others are suspected drug pushers, pickpockets or thieves, with a record of snatching handbags and mobile telephones.

Justice is meted out by two men on a motorbike, one acting as look-out, the other as assassin. Many of the murders have been carried out in public places, in full view of crowds of onlookers. But no witnesses have come forward to testify. "People fear that if they give evidence, they'll be next," says Carlos Zarate, president of the Davao chapter of the Philippine bar association.

Lawyers believe the death squad is run by Davao police, in collusion with Duterte. Bernie Mondragon, the coordinator of the Kabataan consortium of children's advocacy groups, agrees. "These are summary executions," he says. "They are state-sponsored killings. Otherwise, the death squad could not operate with such impunity."

Police deny any involvement and blame turf wars between rival drug gangs. "There have been some killings but, fortunately or unfortunately, the victims were all criminals," says Conrado Laza, the chief of Davao police. He looks incredulous when shown a list of children who have died. "These names are not in our records," he says. Laza claims that the death squad is a myth, "a creation of the media". Despite the 241 unsolved deaths, the Davao police department has received national accolades for reducing crime.

Clarita Alia is a tiny, grief-stricken woman who pushes a vegetable trolley in the public market in the slum district of Bankerohan. Alia used to have seven sons; now she has three. First to die was Richard, 18, who was stabbed outside a café in July 2001. Three months later, 16-year-old Christopher was killed while eating a plate of barbecued chicken at a roadside stall. Bobby, just 14, was attacked as he left a karaoke bar in November 2002. A man plunged a hunting knife into his back. He collapsed in the middle of Bankerohan market.

Weeping frequently, Alia, 48, recounts how a police officer warned her before Richard's death that "they will get my sons, one after the other". She says: "He told me that the Alia brothers were on his 'order of battle'. Later, after Richard and Christopher were killed, the police warned me that Bobby would be next."

The Tambayan Centre, a charity that works with youth gangs, smuggled Bobby out of Davao and placed him in a shelter in General Santos, another city on Mindanao. But he was unable to adjust and returned to his mother. Soon afterwards, he was killed. "It was a terrible blow, because we all knew it was coming," says Tambayan's programme officer, Pilgrim Gayo-Guasa.

The Alia brothers had been in and out of trouble for alleged crimes ranging from theft and solvent abuse to possession of a knife. "I don't believe they committed any grave offence," says their mother. "Whatever they did, my sons didn't deserve to die."

Duterte talks tough and packs a .38 pistol. He rides a Harley-Davidson and runs the city like a Mafia boss. He rarely goes into the office, patrolling the streets at night and sleeping until noon. In the past, he has posed as a taxi driver and street vendor to catch criminals. He has been known to slap errant motorists in the face. Children have been dragged to City Hall for a beating.

The mayor is a one-man crusade against crime, but he loathes the drug trade with a particular vengeance. He went on local television to read out lists of alleged peddlers and addicts, warning them of dire consequences unless they left town. In the ensuing weeks, many people named were killed. Others were targeted after being picked up by police, murdered within days - or even minutes - of being released.

Duterte's zero-tolerance policies are enormously popular. The president of the Philippines, Gloria Arroyo, has appointed him her special adviser on law and order. His constituents credit him with transforming the image of Davao, once the most lawless city in the Philippines. Callers to talkback radio extol his achievements. The summary killings were the main issue in this week's election, which saw him swept back into office with a big majority.

Sofronio Jucutan, the president of the Chamber of Commerce, says the elimination of criminals is good for business. "We don't condone summary killings, but we want society to be cleansed of its scum," he says. "These people are garbage and, just like any garbage, you have to dispose of them." He adds: "But we are a Catholic country and we value human life."

At one of his campaign rallies, Duterte, 59, told the crowd: "If I win, more criminals will get killed because I have vowed to protect the people of this city. It's true that there have been killings. But who were those killed? Weren't they criminals? They were all fools. Now if you tell me you won't vote for me because I've killed many people, then don't vote for me."

In an interview, he is more circumspect. "If you are asking me whether these are state-sponsored killings, they are not," he says. "But I am pleased that these criminals are no longer around to bother law-abiding people." Cracking his knuckles, he says: "If you deal in drugs, eventually you will die. Sometimes, in this world, you have to pay for your sins."

The interview follows an eve-of-election press conference, called to refute a claim by his mayoral opponent, Benjamin de Guzman, that Duterte was plotting to assassinate him. Holding court in a Chinese restaurant in Davao's Grand Men Seng Hotel, the mayor pokes fun at his rival. "If I kill de Guzman, it will not be because I want to win the election," he says. "It will be a mercy killing, to put an end to his agony. It will be political euthanasia." The local journalists giggle sycophantically. Duterte, mightily pleased with himself, repeats the joke several times.

The mayor is a tightly coiled spring of a man, with a cold smile and elegantly manicured fingernails. He quotes, variously, from Virgil and the Bible. According to one story, much repeated, he once took a notorious criminal up in a helicopter, opened the door and threw him out.

The local television station has footage of him kicking the body of one of the death squad's victims - to check he was dead, he explained afterwards.

Duterte's word is law in Davao. Police raiding premises without a search warrant announce that they are acting "on order of the mayor".

"There is an atmosphere of fear," says Zarate, the lawyer. "People dare not go against him." But Patricia Ruiviva, Duterte's chief of staff, says his macho image hides a soft centre. "Children regard him as a father figure," she says. "He is easily moved by poverty and injustice."

Does she think he is responsible for the killings? She pauses, and then says no, citing the "unique dynamic" between Duterte and his mother. "His mother is the only person he fears."

Before he went into politics, Duterte was a lawyer who defended dissidents under the Ferdinand Marcos dictatorship. He served two terms as mayor in the Nineties and returned to the job in 2001. Since then, the number of mysterious killings has soared. The victims so far include 42 people aged 18 and under. None of those stabbed or shot at close-range in the head have been big-time players in the drug trade, according to locals.

The killers, believed to be police officers, former Communist rebels and guns-for- hire, are growing increasingly bold. One man was gunned down in a public minibus in front of his family; two were shot dead outside a church. A victim who survived and was preparing to testify changed his mind after eight armed men visited his house. One member of the death squad, who works mainly as a bodyguard, told a friend: "Now and then I go and do a job for the mayor."

Eighteen-year-old Gerald Abensay, arrested after stealing a stereo in January, was murdered two days later in Bankerohan. He was left lying in a pool of blood, but survived for an hour, gasping for breath and crying for help. Police arrived shortly after the shooting, but ignored his pleas and kept bystanders at bay. The episode was captured on videotape.

"The mayor is playing God," says Mondragon, the children's advocate. "He decides who will live and who will die. He is investigator, judge, jury and executioner. The crimes committed by these people, if ever proven, don't deserve the death penalty. We are supposed to be a civilised society that believes in the rule of law."

Zarate says: "We want the community to unite and denounce these summary executions. How many deaths will it take before we say enough?"

Alia, meanwhile, lives in dread. After Bobby was killed, strangers tracked down her two youngest sons, Fernando, 13, and Raymond, 7, who are living in a shelter. She has been warned that another son, 25-year-old Arnold, will be next. "Why are they targeting my family?" she asks. "What have I done to deserve all these deaths?"