Nigerian prosecutors have decided not to press charges against a 15-year-old girl detained after killing a man who had attempted to rape her.

Police said she stabbed the man, a friend of her father’s, in March when she had gone to his house to do chores.

But state prosecutors in the commercial capital, Lagos, say there is no evidence to support a murder charge.

The teenager has been freed at a time of public protests over a wave of rapes and killing of women in Nigeria.

Thousands have recently signed a petition calling for an end to sexual violence.

Many Nigerians say the country’s legal system makes it hard to convict suspected rapists and blames women when they are victims of sexual assault.

Magistrate Philip Ojo said, in response to advice from Lagos State’s Director of Public Prosecutions, that the teenager should be freed from custody as the “ingredients required to prove the offence of murder against the suspect were not all present.

“Also clearly intention to kill or cause grievous bodily harm to the deceased cannot be established,” he said on Wednesday.

After the 51-year-old man had been killed, the teenager was held at a correctional home for girls in Lagos.