Mexican authorities confirmed Thursday that three Americans missing in the border city of Matamoros for more than two weeks have been found shot to death.
Officials said they are looking into a witness statement that the abductors identified themselves as part of the "Hercules" group, an elite public security unit that patrols the Tamaulipas state frontier with the United States. The state prosecutor said nine members of the team are being questioned.
Tamaulipas state prosecutor Ismael Quintanilla Acosta said Thursday that the victims' hands and feet had been tied, and they had been shot in the head the same day they were kidnapped, October 13.
The deaths of Erica Alvarado Rivera, 26, her brothers, Alex, 22, and Jose Angel, 21, and her 32-year-old boyfriend, Jose Guadalupe Castaneda Benitez, as they traveled to visit family is the third high-profile case in recent months that links security forces to extrajudicial killings.
Dozens of police have been arrested in the state of Guerrero in connection with the disappearance of 43 students in late September.
And according to a National Commission on Human Rights report released last week, in June the army killed 22 suspected gang members in Mexico state and then altered the scene and intimidated witnesses to hide the fact that most were executed after they surrendered. Three soldiers face murder charges.