Police in India say 10 men are in custody, after a 21-year-old woman was raped by two apparently unrelated groups of men on Christmas Eve.
She was visiting friends in Pondicherry when she was abducted by three men and raped by one of them, officials say.
She found her friends after that ordeal but they were all confronted by another group of men who singled her out and gang-raped her, according to police.
The last suspect was arrested on Friday and police say they have confessed.
The suspects have been remanded for 15 days, but they are yet to be formally charged in court. None of the suspects has publicly commented on the allegations made against them by the victim.
Pondicherry Senior Superintendent of Police Monika Bharadwaj told the BBC that this was a particularly bizarre and brutal sequence of events.
It comes just days before India marks the first anniversary of the death of the student whose gang-rape on a bus in Delhi sparked unprecedented public outrage, leading to changes in India's laws against sexual violence.
The incident took place in Pondicherry's port city of Karaikel. When the woman was briefly left alone after her friends went into a house, she was abducted by three men.
"One among that group of three people sexually assaulted her," SSP Bharadwaj told BBC Tamil citing the victim's account of the sequence of events.
She managed to make contact with her friends who came to help her after that ordeal.
"When they were going back they were waylaid by a second group, who again picked up the victim and she was taken to a secure place. There again she was sexually assaulted six times."
According to police, the attackers were not known to the victim and these appear to be unrelated attacks.
Two police officers have also been suspended for initially refusing to register the victim's complaint.
The woman was taken to hospital where she was treated for her injuries and is said to be in a stable condition.