More than one million people have signed a petition demanding justice after three men were told to cut grass as punishment for allegedly gang-raping a 16-year-old girl in Kenya.

In a case which has since sparked outrage worldwide, a 16-year-old girl was walking home from her grandfather's funeral in a village in Butula, western Kenya, when she was allegedly attacked by six men in June.

After the alleged rape, the six men threw the teenager's body down a 12ft (3.6m) sewage pit, where she sustained further injuries. The girl, known as Liz, was eventually pulled out by fellow villagers after hearing her cries.

Liz was able to identify three of her alleged attackers, who were promptly hauled off to the police station by angry locals. After police promised to punish the men, they handed them special machetes known as "slashers" and told them to cut the grass outside the police station. When they were finished cutting the grass, the three men were released.

The case soon caused outcry, with Kenyans expressing their anger and dismay via twitter using the hashtags #JusticeforLiz and #StandwithLiz. After hearing Liz's story, Nebila Abdulmelik, a women's rights activist in Nairobi, launched an online petition with the international campaign group Avaaz demanding the men be brought to justice and the officers involved in the case disciplined.

The petition calls on Kenya's Inspector General of Police to "deliver justice for Liz including the immediate arrest and prosecution of her rapists and full disciplinary action for the police officers who dismally failed to handle her case."

It adds: "By holding these police officers to account you will send a strong message to police everywhere that rape is not a misdemeanour, it is a serious crime, and if police do not uphold the law they will be held to account.

"We call on you to ensure Liz's case is a turning point to end the war on girls."

'World's worst punishment for rape'

After the petition was featured in Kenya's Daily Nation, the newspaper which originally broke the story, more than one million people worldwide signed the petition, which expresses the hope that "Liz's nightmare marks a turning-point in Kenya's rape epidemic".

"Letting rapists walk free after making them cut grass has to be the world's worst punishment for rape. It is an absolute failure of the entire system and an absolutely shameful response by Kenya's police," added Abdulmelik.

According to a report released last year by the United Nations with the Kenyan government, at least 32% of females under the age of 18 in Kenya experience some form of sexual assault. A report from Kenya's national commission on human rights in 2006 adds that a girl or woman is raped every 30 minutes in the African country.

The 16-year-old is currently in currently in a wheelchair after receiving a spinal injury and developing obstetric fistula as a result of the rape and attack.

Since the public outcry surrounding the case, Kenyan police chief David Kimaiyo tweeted to say that suspects have been arrested and are awaiting their hearing. However, he did not specify how many were arrested and the tweet has since been deleted, according to CNN.

Kenya's Coalition on Violence Against Women said: "This is yet another example of blatant impunity and repeated noncompliance by the police and other government authorities. Rape and other gender crimes have consistently been treated as lesser crimes - this is unacceptable."