The muddy waters of Calumet Sag Channel have fondled many a dead body. Gang killings are rife in Chicago. But when the daughter of a school superintendent was whipped, shaved, tied with wire to a manhole cover and thrown alive off a bridge, a city almost inured to gangland crime took note.

The shock was due less to the brutality of the murder than the sex of the torturers. They were girls. Girls in a gang. The motive for the killing? Jealousy. Kristin Ponquinette had been flirting with 'our baby-daddy' - someone else's boyfriend.

Residents of the suburb immediately demanded bigger police patrols. The streets needed to be 'swept clean', they said. Briefly, there was a semblance of change. Four girls were charged and imprisoned. Then there was quiet again.

Local residents insist the killing was a one-off: most female gang killings are confined to the South Side of Chicago. Go there if you are looking for 'cold, cold killings', one said; 13 people were murdered on the South Side in July.

Until Kristin Ponquinette's death last year, women kept a low profile in Chicago gangs. They offered alibis, or acted as drug-carriers or, at worst, 'seductresses'.

This has changed. Brutality has become the hallmark of female gang activity in a city already known for its violent history. One woman peppered a passer-by with bullets in a drive-by shooting while her own two-month-old twins sat in the back seat of the car; she mistakenly thought her victim was a member of a rival gang. In September, three teenage girls pleaded guilty to murder after luring two men to a park, kissing one, then shooting them both in the head - another 'revenge' killing.

'Women have become the perpetrators,' says Charles Brown, assistant director of the Chicago Boys and Girls Club, a South Side rehabilitation project for female gang members. 'These girls feel like they have been in the dark ages for so many years, just having babies, having sex, doing drugs. Now that they have the expertise, they want recognition, they want control. They want to start shooting. They feel they can control the gangland scene.'

Police insist that crime among women gang members is still 'on the periphery'. But youth workers believe otherwise. 'Killing is now as much a girl's privilege as a boy's,' Mr Brown says. 'There is no distinction between the sexes when a gun is in the hand.'

Josie, 17, has been a gang member since she was 11. She lives on Chicago's South Side with her mother and a sister. Her home is covered in graffiti and its shattered windows and split bricks show the pattern of past bullets.

Josie goes to school on the South Side. Half of the 3,000 pupils are girls. All belong to gangs, she says. Every day they must decide whether to walk the side streets to school and risk being beaten up, or take the main road and face the threat of drive-by killers.

Teachers know the risks pupils face: two students have died in gang-related killings in the past four years. Ceremonies were held at the school to help the children feel that life is something to be valued, that they will be missed if they die. Then things returned to normal. Josie says the killings are remembered only as part of gang folklore.

All gang members go through some form of initiation. Josie endured the 'Run Down the Lane' in which she was forced to run between two lines of people who beat her with chains and belts. Rules governing beatings forbid members from kicking an initiate in the genitals or face.

There are rules for everything, Josie says. Members are 'butt-whopped' if they disobey. As well as performing their regular duties - crack-dealing and recruiting - members are told to report to meetings three times a week. The meetings start with a recital of the gang oath. Knowing its wording by heart is viewed as a sign of loyalty. After that complaints are dealt with and plans discussed. If anyone has died, a short service is held. Then, says Josie, the chanting starts.

'Someone will shout: 'I don't like Jim'. Then we wait for someone else to say the same. When more than five people have shouted out, we all start chanting: 'Jim, Jim, Jim'. Then we go out, find Jim and beat him up.

'Gang life is all about killing. They just kill, kill, kill. I'm tired of it. I've been moving around trying to avoid members for ages. But girls keep stopping me. 'You left your gang?' they ask. I don't say nothing. They would get me if they found out that I wanted to leave. I'm just going to wait a while, then maybe move to another state.'

Moving elsewhere would only mean coming into contact with another gang, Mr Brown says. Many girls who attend high school on the South Side are thought to belong to gangs for protection.

Little research has been carried out on female gangs in the US. But mixed gangs, some with up to 25,000 members, are believed to be active in 177 of 189 major cities, according to a report by the University of Southern California's Center for Research on Crime and Social Control.

In some cities, community, church and school organisations work together to try to dissuade girls from joining gangs. In Chicago, there are organisations with aspirations but no programmes. The Boys and Girls Club is the only after-school club aimed at female gang members. The club tries to deter membership by encouraging members to think independently.

'We create an environment where self- esteem is enhanced,' Mr Brown says. 'By teaching girls about self-help and personal responsiblility, we hope to show that there is life outside gangs, that there is another way of filling time, finding an identity and winning prestige.'

Renee, 16, has been in a gang for one year. She loves it. She rolls back her T- shirt without embarrassment and shows me a scar just above her left breast. 'I got this from a stabbing,' she says. 'I've got four others.'

Renee's gang, Sisters of the Struggle, had not insisted on an initiation ceremony. As long as she knew the oath, attended meetings and did her duties, they were happy. Was the group political? She didn't think so and didn't care. What were her duties? To get money, find guns and deal drugs. What kind of drugs? Heroin. She was awaiting a hearing at the juvenile court for heroin trafficking. Police say she was caught carrying five packets of the drug.

In a jumbled, incoherent rush, Renee tries to explain the intricacies of gang life, the squabbles, the fights between rival groups. Her 'baby-daddy' - the father of her child - had been stabbed. There had been a 'mammoth' fight. A girl had been attacked with an ice pick. Someone else had broken a leg. She went on and on, talking furiously, inarticulately.

Her parents did not know anything about her activities after school. But they knew about her knife. But then everyone carried a knife. Renee drew a picture of the blade. It was more commonly used for slicing open cardboard boxes in supermarkets, she explained, and demonstrated the hacking motion. For the street, it was more useful for slashing.

Athena, a large, obese woman, was in a 'lady-gang' until four months ago. She has come to the juvenile court to support a friend on a drugs charge. In the beginning her gang promised her 'family': she would do her 'deeds' and they would give her 'love and guidance'. It sounded attractive. Athena had no family. So she took drugs to 'sisters' in prison and recruited gang members. Evenings were taken up with the sale of drugs. Then she discovered that the 'love' she sought required absolute loyalty and the 'guidance' was enforced through violence.

'We called each other sisters, but there was no real loyalty. If ever you were getting beaten up and you looked round for your sister, she had run - far, far away. There was no love there - no positive love anyway. Everything was negative. 'Show your loyalty by butt-whopping that boy', they would order. If you refused, it was counted as disobedience.

'The more I grew up, the more I realised this was not the kind of love I wanted. I didn't want to have to take someone else's life away to win love. One day a 15-year-old boy came into our area. We put on masks - a paper bag, a hood, or a scarf - then we jumped on him and hit him with a chain until it broke. We found a gun in his jacket. One of the girls shot him.

'Afterwards we put him in a car boot and dumped him in an alley. He lay there for an hour with people walking past before anyone took the trouble to find out if he was dead. I went along to the funeral. The preacher blamed the boy's death on his household - said it hadn't treated him right. He said this boy had just grasped out for help in the wrong place.

'The next time the chief said, 'Take care of that girl', I couldn't do it. I didn't even know the girl. She had been messing about with boys, they told me - stupid, unnecessary shit. When the gang realised I hadn't joined in they made me 'run down the lane'. Then I was released.'

Athena's life is in ruins. She is a crack addict and is in therapy. She rises unsteadily to her feet and says she is glad to have talked and picks up her gift bag with the sad face of a Pierrot clown on it.

Athena left her gang because she could no longer tolerate the demands of her chief. But girls who join for the excitement or to establish an identity find it harder to leave. The Boys and Girls Club tries to encourage gangsters to go back to school; police officers occasionally drop a particularly young, pretty or vulnerable girl into the lap of a benevolent organisation, but apart from that little is done.

Left alone by the do-gooders, the girls get on with their business. They operate in pairs, in cars or on foot. An outsider standing on the pavement might think the street was empty. But the gang members are there, ready to pounce.

(Photograph omitted)