Eleven people, including a 12-year-old boy and a 15-year-old girl, have been arrested on suspicion of raping a woman in her home in Liverpool.
The 43-year-old woman, described by police as vulnerable, was attacked at a property in Anfield on 24 September.
Paramedics called police to report the woman had been sexually assaulted.
Two men aged 19 and 18, eight boys aged between 12 and 16, and the girl have been released on bail. Merseyside Police said they were investigating whether any other people were involved.
Det Supt Tim Keelan, said: "The victim has been distressed by her ordeal and is being supported by specialist officers.
"This was an appalling attack on a woman in her own home and we would urge anyone who has information, which could help us bring those responsible to justice, to come forward."
She no longer lives at the address, police said.