Shamin Akhtar, 58 (pictured), took the drastic action after her youngest daughter Naila Afsar refused to honour a pact she had made with her sister, for their children to marry.
After breaking off the engagement to her first cousin Amraiz Khan in July 2009, Naila Afsar ran away to Newcastle to secretively marry the man of her choice because she thought she would be killed.
Detectives have described the mother-of-eight’s crime as “every child’s worst nightmare”.
Shamin Akhtar, of Kirkwall Drive, Holme Wood, was unanimously found guilty by a jury after a four-week trial at Preston Crown Court.
Her son Shamrez Khan, 34, of Moor Avenue, Great Horton, Bradford, and her son-in-law Zahid Mahmood, 36, of Empress Street, Accrington, also pleaded guilty to false imprisonment, kidnap and two counts of administering a drug with intent.
The victim’s father Mohammed Khan, 57, of Scotchman Road, Manningham, and her sister Saima Mahmood, 30, of Accrington, were both cleared of wrongdoing by the jury.
The court heard that Naila and her new husband Afsar Saddiq were in bed at their Newcastle home, when they heard banging on the door.
The victim’s brother Shamrez Khan then appeared in the bedroom shouting while her mother and brother-in-law waited in the living room.
The 23-year-old was then pressured to go back to her sister’s home in Empress Street, Accrington.
Unknown to the victim, her mother, her brother and brother-in-law then travelled back up to Newcastle in the middle of the night, confronted Mr Saddiq and collected her belongings, including her passport.
Her mother then returned to Accrington claiming she had sorted the situation.
Later, the victim was persuaded to drink some warm milk, which made her dizzy and sick.
Soon afterwards she was discovered lying in a car looking drowsy by police officers.
Judge Simon Newell refused Shamin Akhtar bail yesterday.
All three have been remanded in custody and will be sentenced at Burnley Crown Court on July 10.
Speaking outside court DS John Rigby, from the community cohesion team said: “The victim has gone through a major ordeal and has been supported every step of the way by specially-trained officers and partner agencies.
“What she has been through is every child’s worst nightmare. She did not want retribution but she wanted to show her family what they had done was wrong. I encourage any member of the community to come forward and speak to us if they are concerned with an honour- based crime.”
Speaking outside court, the victim’s father Mohammed Khan said: “I miss my daughter.
“When I die it is my wish for my youngest daughter to be present at my funeral.”
His barrister Afzaal Anwar also made a statement on his behalf, he said: “My client always maintained he was innocent of these allegations.
“The police and prosecution had charged him on a cultural prejudice simply for being the father of the family”
Barrister Ken Hind, also read a statement on behalf of Saima Mahmood. He said: “This is still a tragic day for her as members of her family have found themselves in custody facing very serious charges.
“She hopes the family will be reconciled.”