The driver of a bus on which a 14-year-old girl was raped was unaware of the attack, his company has said.
The schoolgirl was attacked on the top deck of the 57 bus as it left Silverburn shopping centre in Pollok, Glasgow, at about 10.30pm last Friday.
She got on the bus with a friend and they took a seat downstairs.
The victim went to the upper deck where she got into a conversation with two men who boarded the bus in the city centre.
She was then assaulted and raped by both of them.
Her friend, also 14, went up to see her and raised the alarm with passengers downstairs.
A woman and two men came to the girls' aid. They all left the bus two stops along from Silverburn.
The passengers are said to have waited with them until they got another bus home, thought to be in the Darnley area of the city, where police were contacted.
No CCTV footage is available from the bus while Strathclyde Police are appealing for those passengers to come forward to help their investigation.
First Glasgow, the bus operator, said the attack was not reported to the driver and the company is working with police to find the men involved.
A spokesman told BBC Scotland: "Our driver was not aware of the assault. Unfortunately, the incident took place on the top deck of the bus and therefore out of our driver's eyeline and no-one on board approached our driver to report a disturbance.
"The driver ejected the two males in question sometime later in the journey - this was due to separate unruly behaviour.
"Our thoughts are very much with the victim of the assault."
Both of the attackers are said to be aged around 18 to 20.
One is about 5ft 10ins, with a shaved head and wearing a black jumper. The other man has brown, spiky hair and was wearing a tracksuit which may have been grey, with a body warmer or jacket.
Detective Constable Jackie Carroll said the girl was left "traumatised" by the attack.
She said: "This was a very frightening experience for the young girl concerned and, thankfully, she was assisted by her friend and the good samaritans on the bus who ensured she got home safely.
"She has been left traumatised by her ordeal.
"We're continuing extensive inquiries into the incident and would like to trace two men and a woman who came to her assistance as they will have vital information which could help with our investigation.
"We know that the men responsible boarded the bus in the city centre. The men were very loud and using crude and lewd comments to other passengers.
"The bus driver ejected the two men from the bus at Pollokshaws Road (near Queen's Park) around 12.30am.
"I would like to speak to anyone who may have been present on the bus at the time of the attack, as it is imperative we trace these men."
Anyone with information can call Greater Glasgow CID on 101 or Crimestoppers anonymously on 0800 555 111.
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