By Nick Miles
BBC Correspondent in Mexico City
Hundreds of murders have shocked Mexicans
The Mexican attorney general's office says it is investigating the possibility that a number of women murdered in the northern border town of Ciudad Juarez may have been killed by organ traffickers.
In the last 10 years more than 300 women have been murdered in the town, with several hundred more missing.
Despite a number of convictions for some of the crimes, the killings have continued.
This is just one more twist in the series of killings in Ciudad Juarez.
In a press conference in the town of Chihuahua, federal prosecutor Carlos Vega said 14 of the victims may have been kidnapped and killed so that their organs could be sold.
Mr Vega said that organ smuggling was not the only line of investigation but that "several details support the idea that these women were killed for body parts".
Until now the case has been handled by state prosecutors, but organ trafficking comes under the jurisdiction of federal investigators.
The wave of killings and the lack of progess in resolving them has shocked and angered Mexicans, and brought condemnation from human rights groups like Amnesty International.
There have been a number of arrests made in recent years but only one conviction, for five of the murders.
More than 80 of the killings have shown marked simliarities, nearly all the victims were young women, factoryworkers who were strangled and whose remains were buried in the scrub desert on the outskirts of town.
Investigators believe that the similarities indicate the work of a serial killer or killers.
Two local men are currently in custody charged with a number of the murders.
The hope of many in Ciudad Juarez is that with the federal government finally getting involved in the investigation the wave of killings will be brought to an end.