Five men who were involved in the sex trafficking business are facing lengthy jail sentences.
The gang forced women to work as prostitutes in London brothels
Flamur Demarku, 33, his brothers Agron and Bedari, both 21, and friend Izzet Fejzullahu, 32, were found guilty of trafficking and prostitution offences.
Another Demarku brother, Xhevair, had pleaded guilty before the trial.
Southwark Crown Court had heard how the gang bought women for cash from other traffickers and then forced them to work as prostitutes in London brothels.
All five men, who are Albanian, will be sentenced on Thursday.
The operation was discovered after a tip-off from the BBC's Six O'Clock News, which had started an investigation into the disappearance of a Lithuanian girl.
The reporters learned that the girl was ringing her parents from London, and police found her when they raided a brothel in Hounslow in December 2004.
She was being forced to work as a prostitute and was known as "Veronica from Italy".
Over the next four months they observed comings and goings at seven other addresses owned or rented by the gang in the Hounslow area, five of which were actively being used as brothels with at least five girls working from each one.
In April 2005 they carried out a series of raids, seizing documents relating to Lithuanian women, evidence of money transfers, menus of sexual services and many thousands of pounds in cash - in one case £30,000 was found at a single address rented by the gang.
Undercover officers posed as clients to gather evidence against the pimps and to try to identify women in need of help.
Flamur Demarku (left) and his brother Bedari denied the charges
Among them was another young Lithuanian woman from the city of Siauliai, a 19-year-old student who had been a virgin before she was sold to the gang.
She was made to lose her virginity the next morning for £40 - an experience she described as "agonising".
In the month that followed, she was forced to have sex with hundreds of customers, earning the gang tens of thousands of pounds.
She was finally found by police during a covert visit to a brothel in Hounslow and rescued during a raid 10 days later.
Prosecutor Michael Holland described her situation as being "as close to being a slave as it is possible to be in a Western country".
Bedari Demarku was cleared of one charge of causing sex without consent.
Xhevair Demarku had pleaded guilty before the trial
Detective Superintendent David Eyles, who heads the unit investigating vice, said: "This gang of men preyed on vunerable Lithuanian women, luring them into this country then holding them against their will and forcing them to work as prostitutes.
"These young women have been traumatised by their exploitation and in one case had their first sexual experience under these horrendous circumstances."
The trial began as Channel 4 was repeating its acclaimed drama Sex Traffic, which involves Albanian pimps, and defence lawyers feared this might unfairly prejudice the jurors.
The men, who are all from Albania, will be sentenced on Thursday.