Official investigations into the slayings of hundreds of women near the U.S. border have been rife with carelessness and neglect, the National Human Rights Commission said in a report presented to Mexico's Senate on Monday.
At least 263 women have been killed in Ciudad Juarez since 1993 and more than 4,500 have been reported missing, according to the report.
The 1,600-page report charges that officials have used falsified evidence, torture and questionable investigative techniques in probing the cases, echoing criticisms made in August by the human rights group Amnesty International.
"The report documents and demonstrates what many voices have denounced for some time: the intolerable weight of negligence, lack of attention, omissions and even discrimination and tricks which have characterized the behavior of many agents," said commission president Jose Luis Soberanes.
He suggested that officials had given little attention to the cases because the victims were poor. "If the women had not been so socially vulnerable, it would have been difficult to show such negligence," he said.
He said at least 89 witnesses had been tortured to prompt testimony. Representatives of victims say they believe some of those arrested were innocent targets of fraudulent evidence.
Soberanes said it was time for the government "to answer a question asked by national and international society: Who killed them?"
"Either we answer that question or we are making fools of ourselves," he said.
In one example of the official carelessness, Soberanes said, documents about some of the slayings were left in an office that was invaded by homeless people seeking shelter from the winter cold. They burned the papers for heat.