Chief investigator of Mexico mass killings goes missing
Mexican prosecutors say they are deeply concerned for the safety of the prosecutor who is leading an investigation into the killing of 72 foreign migrants.
The wife of Roberto Suarez told the BBC he had been missing since Wednesday, the day after the migrants were found dead at a ranch in Tamaulipas state.
A police officer who was travelling with him has also disappeared.
Mr Suarez was one of the first people to find the migrants' bullet-ridden bodies at the ranch near San Fernando.
The only known survivor, an Ecuadorean man only identified as "Freddy", said the Zeta drugs cartel had tried to force the migrants to carry out assassinations for them.
The 58 men and 14 women were from South and Central America and had been trying to reach the United States.
In an interview with the BBC on Friday, a spokesman for the prosecutor's office in Tamaulipas, Ruben Dario Rios, would only confirm that Mr Suarez and an unnamed local policeman were still missing.
"We have launched a major search for them and are obviously very worried," he said.
However, the wife of the missing investigator, Norma Nelly Aguilar Hernandez, told the BBC that she feared the worst.
"I am almost certain my husband and the other man were kidnapped," she said.
"I can only assume that those who abducted my husband are connected to organised crime in this region," she added.
Mrs Aguilar explained that as far as she knew, her husband had never received any direct threats from local drug cartels.
However, she conceded that his most recent work as the chief detective working on the massacre case was highly sensitive.
Mexico's President Felipe Calderon was asked by reporters on Friday to comment on the latest development in the investigations into the massacre, but stressed that it was too soon to speculate.