Police are investigating a reported pack rape of a woman by a group of men she met at a popular swimming spot near Lyttelton on Sunday.
The woman, in her 30s, told police she was sexually violated by a group of men she met on a raft anchoredfor swimmers at Corsair Bay.
The attack happened later in the day in Christchurch.
Detective Sergeant Ross Tarawhiti, of Hornby police, said photos taken by beachgoers between 11am and 3.15pm that day might hold the key to the inquiry.
"We are investigating an alleged sexual violation involving a number of males, some of whom may have been in the Corsair Bay area, around this time," he told The Press.
The men, between four and six of them, ranged in age from 20s to 40s.
The victim was at the beach with a young boy who was part of her family.
"She had a guitar with her which would have stood out to the people who were over there," Mr Tarawhiti said.
He was keen to get hold of snapshots of family and friends at the beach which might contain people in the background of interest to the police or which might be useful in recreating the scene.
He was particularly interested in activities around the raft anchored to the middle of the bay.
Those already spoken to by police said they saw nothing untoward.
