Creteil Clement Guyard  school
A 12-year-old schoolgirl from the Clement Guyard institute in Creteil was allegedly torturedGoogle Maps

French police are investigating a bullying incident involving three schoolgirls suspected of subjecting a 12-year-old to months of torture, including stubbing out cigarettes on her face. The trio were held for questioning by officers in the south-eastern Paris suburb of Creteil after the victim's ordeal was revealed following the last brutal attack.

On Tuesday (12 April), the alleged aggressors, aged between 13 and 15, reportedly intercepted the younger girl as she came back from school and, threatening her with a knife, demanded she hand over €170 (£135, $190). The 12-year-old, given the name Sandra in French media, told Le Parisien newspaper that since she didn't have the money, she was beaten, forcibly undressed, urinated on and had chunks of hair slashed off.

The ordeal lasted about an hour and was filmed by the alleged perpetrators who threatened to upload the footage on social media. Sandra said she was released after stealing food and drinks for her torturers.

She suffered a dislocated jaw and was later found in evident distress by her parents who noticed cigarette burns on her body and alerted police. "It was horrible. She was bloody and had difficulties breathing," the mother the newspaper.

Parents and police later learned that Sandra had been targeted by the girl gang since December 2015. The family said they had noticed money and jewellery had gone missing from their home but didn't suspect their daughter was the culprit, nor that she was being subjected to extortion and violence.

"She kept silent about it, and finally she told us 'I feared causing problems for you'," her father told Europe 1 radio. Schoolmates at the Clement Guyard institute also said they had no idea of Sandra's troubles. "She didn't say anything. She must have been afraid or ashamed," one told local media.

The three suspects were detained by police in a sting operation that saw Sandra contacting her attackers pretending to be ready to give them the money they demanded.

Police investigating allegations of gang aggression, torture and cruelty against a minor under 15 years of age said the three were already known to authorities for episodes of violence against other children. A fourth girl was also quizzed but later let go. Sandra's family said they would now leave Creteil for another area.