Samia Shahid, 28, from Bradford, died in July in northern Punjab.
The Pakistani chief investigator also told the BBC Ms Shahid's father and former husband carried out her murder.
He added he was seeking to have her mother and sister returned to Pakistan to be questioned about their role in the murder.
Two men have already appeared in court in Pakistan in connection with Ms Shahid's death.
Her former husband, Chaudhry Muhammad Shakeel, is accused of murder and is reported to have confessed to strangling her with her scarf, according to local police.
