Mexico Bus Murders: Female 'Vigilante' Sought Mexican authorities are investigating claims that a woman who killed two bus drivers was seeking revenge for the alleged sexual abuse of female passengers. A woman wearing a blonde wig boarded a bus in Ciudad Juarez on Wednesday morning, shot the driver in the head with a pistol and made her getaway. The next day another driver on the same route was killed, apparently by the same woman. Emails claiming to be from "Diana the hunter of bus drivers" were then sent to media organisations over the weekend. "I myself and other women have suffered in silence but we can't stay quiet anymore," the email said. We were victims of sexual violence by the drivers on the night shift on the routes to the maquilas (factories). I am the instrument of vengeance for several women. The newspaper Diario de Juarez reported that a witness quoted the killer as telling the second victim, "You guys think you're real bad, don't you?" before shooting him. Police have not verified the authenticity of the emails, or of a Facebook page set up under a similar name. However, Arturo Sandoval, a spokesman for the state prosecutors' office, said they were taking the vigilante theory seriously. "Now that we have the email in the case file, it indicates that this could have been someone who had had a run-in with a driver of one of his relatives," Sandoval said. There was apparently no robbery in either of the killings. Ciudad Juarez lies just across the border from El Paso in Texas Undercover police are being put on some buses in the city and detectives said they have a sketch of the killer. Weapons searches are also being put in place. Ciudad Juarez, located just over the border from El Paso in Texas, is a notoriously violent city with frequent killings related to the drugs trade. More than 100 women - many of them factory workers - were killed in the 1990s and 2000s after boarding buses in the city. Their bodies were often found weeks or months later, raped, strangled and dumped in the desert or vacant lots. Several bus drivers were arrested in connection with those killings but the cases against them always appeared weak, or their confessions forced. One driver had his conviction overturned, and his co-defendant, another bus driver, died in prison before sentencing. The head of the Chihuahua state Women's Human Rights Centre, Lucha Castro, said it was possible the killer "or someone close to her suffered some abuse by one of these guys." "It's a fact that there are sexual abuse cases on the bus routes," she claimed.