Hundreds march in Nairobi to demand justice for 16-year-old gang rape victim whose attackers were let go after cutting grass

The placards waved outside the office of Kenya's chief of police made a point anyone could understand: "Cutting the grass is not punishment for rape," they read.

The protesters had gathered to demand justice for Liz, a 16-year-old who was brutally gang raped in western Kenya in June and whose attackers were let go after being made to cut the grass by local police. Despite the victim identifying three of the men to authorities no arrests have been made four months later.

Meanwhile the teenager, who was dumped into a 15-foot pit latrine, is still in a wheelchair while she recovers from operations to repair damage to her spine, bladder and bowel.

Protest marches are rare in Kenya, outside of party politics, and the hundreds of women, plus a handful of men, stopped the traffic by waving pairs of knickers and calling for an end to sexual violence.

"We are willing to take our demands to the streets, we've gotten to the stage where people are outraged," said Nebila Abdulmelik, a young activist who started an online petition on the campaigning website Avaaz, after learning of Liz's fate. The gang rape in Busia, a county on the shore of Lake Victoria, has crystallised anger at rising levels of sexual violence in East Africa's biggest economy and official unwillingness to enforce the law.

The victim's mother, who cannot be named, had to effectively bankrupt the family, leasing their only plot of land, to get treatment for her daughter: "Why has no one been arrested?" she asked.

A child protection agency in Liz's home area has passed to the police the names and addresses of six suspects, who have been in hiding, since the case was reporting this month in the Kenyan media.

A petition with more than 1.5m signatures from around the world was handed to the Kenyan police on Thursday demanding that her six attackers be arrested and prosecuted and the state compensate the victim. Under Kenya's sexual offences act the minimum sentence for rape is 15 years and "the state bears the burden" of treating the victims.

"We want the police to do their job," said a woman with a loud-hailer, "rape is not normal."

A police official told the protesters: "What took place we're all aware of and we are making efforts to remedy it to the best position that we can."

One of the police officers in the village of Tingolo, where the rape was reported, has been suspended, authorities said, but none of the attackers have been detained.

A recent study conducted by the UN's children's agency, Unicef, found that almost one in three Kenyan girls had faced sexual violence at school. Research by women's groups estimates that a woman or girl is raped every half hour in the country of 43m people.

As the marchers gathered in the capital, Nairobi, news came of another gang rape overnight in Busia, this time of a 12-year-old girl. Sara Longwe, a 66-year-old protestor, said she had decided to march because rape was becoming more common and people were starting to think it was normal.

"They're raping toddlers and babies," she said. "And in most cases nothing happens even though the perpetrators are known."