Two men carried out a string of sex attacks against women in the Midlands
Peter Livingston Jones, 55, and Raymond Dickens, 53, preyed on vulnerable women and "forced them into prostitution", police said.
They denied all charges against them but were found guilty after a trial at Warwick Crown Court.
A third defendant, 43-year-old Helen Thompson, was convicted of one count of kidnap.
Operation Costa was started by Warwickshire Police's major investigation unit after two victims made allegations against Jones and Dickens.
Det Insp Paul Thompson said: "Over a number of years, Jones and Dickens have taken advantage of vulnerable young women for their own sexual gratification and financial gain.
"They preyed on vulnerable women.
"To start with they flattered them and brought them gifts but this attention soon turned to sexual and physical violence, manipulation and intimidation.
"All this was intended as a way to control them and force them into prostitution."
Jones, of Wheelwright Lane, Coventry, and Dickens had denied all charges.
But a jury found Jones guilty of 11 charges against five victims from the 1990s up to his arrest last year.
This included three counts of rape, one of administering drugs to obtain or facilitate intercourse and one of kidnap.
He was found not guilty of having an imitation firearm.
Dickens, of Langdale Close, Rugby, was convicted of eight offences against three victims in the 1990s - four counts of indecent assault, two counts of rape, one count of procuring a woman to become a prostitute, and one count of false imprisonment.
Jones and Dickens are due to be sentenced on Friday.
Thompson, of Morris Close, Rugby, will be sentenced at a later date.