Three men fed her sedatives then raped her.
Her mother, who had been washing clothes in a stream near their home in Freetown, Sierra Leone's capital, got home to find her child lying on the ground distraught, her legs and dress stained with blood.
"They put dirty clothes in my mouth and raped me," the girl told AFP, without giving her real name.
The family reported the attack to the police and identified the rapists, but no charges were ever brought.
Thousands of children and young girls were raped last year in Sierra Leone. According to police statistics, recorded cases of sexual and gender-based violence almost doubled last year, reaching 8,505 in a population of 7.5 million, up from 4,750 a year earlier.
And of that number, 2,579 cases - around a third - involved the rape of a minor. But, as with the incidence of rape in almost every country, this shocking tally is almost certainly an understatement. "Mary" and her family plucked up the courage to report the crime.
"We have a culture of rape in Sierra Leone," admitted Chernor Bah of the UN Global Education First Initiative at a demonstration in Freetown last month where more than 500 black-clad protesters took to the streets over violence against women.
"The rape of minors is a national problem," rally organizer Asma James said. "The situation is sad, selfish, barbaric and inhuman and requires all of us, women and men, to speak up." Just weeks before, the country was shaken by the rape of a five-years-old girl by her 28-year-old uncle.
Her attacker raped her anally, crippling her spine. Doctors at the Aberdeen Women's Centre in Freetown, which helps women and girls who have suffered from sexual violence and rape, said it was unlikely the child would ever be able to walk again. The attack sparked outrage, with many people demanding that child rapists face a lifetime behind bars - calls echoed by President Julius Maada Bio himself recently.
"Let me be very clear: men who rape girls deserve to be jailed for life," President Bio said as his wife the First Lady Fatima Bio launched the campaign called: "Hands off Our Girls".
Reports of rape and the sexual penetration of minors, as child rape is legally termed, have steadily increased, according to the Freetown-based Rainbo Initiative, which provides free medical services and counseling to victims of sexual and gender-based violence.
Figures collated by the centre show that in 2018, 76 percent of rape victims were aged 15 years or younger - including babies. The rest of the victims were aged between 16 and 20. And every month, an average of 149 victims fell pregnant as a result of rape.
"Children are brought to our centre in tattered clothes covered with blood stains," Executive Director Daniel Kettor told AYV when contacted. In Freetown alone, there were 1,491 cases of sexual abuse reported between January and October 2018, with the youngest victim just seven months old and the oldest aged 85. "Amongst the survivors, six were HIV-positive and 484 fell pregnant after being raped," Kettor said.