The alleged attack happened in Muelheim, a city in the western German state of North Rhine-Westphalia
The group of boys outside a police station
A group of youths aged 12 and 14 have been detained on suspicion of gang-raping an 18-year-old mentally disabled woman in a playground.
The gang, three of them aged 14 and two 12, are accused of luring the mentally disabled woman to a playground in a city park.
They then reportedly attacked the woman and dragged her into some bushes while filming the ordeal on their phones.
A police spokesman said: “There was violence, massive violence.”
People living nearby were alerted to the commotion behind their house when their dogs would not stop barking.
After about an a 61-year-old man walked out of his home towards the bushes and reportedly saw the woman and two suspects who immediately fled the scene.
The man called the police who came and took the woman to hospital where she was treated for unspecified injuries.
The woman gave a detailed description of the alleged perpetrators.
Later on the police force arrested five people.
As children under the age of 14 cannot be prosecuted in Germany, the two 12-year-olds were handed over to their parents.
The three 14-year-old boys spent a night in a police cell before they their parents picked them up, according to reports.
Police spokesman Peter Elke said: “After we determined that two of the group members are 12 years old and therefore are not criminally responsible, we handed them over to the parents.
“The three 14-year-olds were arrested and detained overnight. They were released on Saturday after interrogation.
A police investigator who wanted to remain anonymous told local media that an arrest warrant “had no chance of success in this case”.