Lindsay Murdoch, Jakarta – There is one small neighbourhood in Jakarta where thieves dare not go. Doors are often left unlocked and everybody knows everybody else. In a city where hunger is endemic, chickens roam freely. Children play soccer and teenagers strum guitars.

All who come here have business, friends or relatives – or they just don't come. For one very good reason. "We kill the criminals," said a man sitting on the porch of his small, corrugated-iron corner shop.

In this city of 13 million people police are struggling to control a wave of vigilante killings. First the local residents catch the thief, then they beat him up, pour petrol over him and set him alight. When the police arrive, usually late, they find a corpse or corpses and no witnesses.

Jakarta's morgue has introduced a new category, "victims of mob violence", into its statistics. Since the start of the year 103 bodies have been listed.

Police said they were unable to name suspects in an attack at a bus terminal in East Jakarta where five men were set alight. Locals say the men were caught demanding money from passengers of a minibus. Somebody yelled "thieves" and the mob grabbed them and went into a killing frenzy.

"We've had difficulties locating and arresting [the murder suspects] since they mixed with the crowd at the time," Sergeant-Major Sri Suwarno of the local police said.

Siti Linda said her husband, Nurdin, one of the victims, had phoned her earlier in the day and said he would arrive home with money. She was seven months pregnant, and Nurdin was supposed to take her to hospital that night for a check-up. But she received little public sympathy for her loss. "He's not a criminal ... why did the crowd mob my husband to death?" she sobbed.

The commander of the Jakarta police, Major-General Nurfaizi, condemned the brutality and said the public had lost control. "It's a bad symptom in society. You must ask the public themselves what the motive is behind all this street justice."

The police appear powerless to stop the killings. In a country of 220 million people there are fewer than 200,000 police, one of the lowest police-to-civilian ratios in the world.

A Jakarta police spokesman, Lieutenant-Colonel Zainuri Lubis, said investigators found it almost impossible to find witnesses in street justice killings. "Public morality has turned bad," he said.

Recently a crowd forced police to release four robbery suspects who were in the police detention house in East Jakarta, he said. "After releasing the suspects the crowd mobbed them ... the four police could do nothing at the scene." President Abdurrahman Wahid has ordered an increase in the number of police, but insufficient funds are available.

There is another form of illegal justice emerging in Jakarta which the police are also either unwilling or unable to stop. About 1,000 members of a radical group called the Front for the Defence of Islam have started raiding entertainment venues they regard as decadent.

Police stand by and watch as they confiscate liquor and search patrons of discotheques, hotels and other establishments. In some raids their members, wearing white robes, have used baseball bats to smash up premises.