Three US Citizens Shot Dead In Mexico

Mexican authorities are looking into the deaths of three US citizens who were shot dead on a visit to see their father.
The investigation is focused on a specialist security unit known as "Hercules", made up of former marines and soldiers who police hot zones for crime.
Nine of 40 Hercules officers, working in the violent border city of Matamoros, are being questioned over the deaths of four people, including the three US siblings.
According to a witness, brothers Alex Rivera, 22, and Jose Angel, 21, arrived at their father's house to find security personnel hitting their sister Erica, 26.
When the brothers intervened, the Hercules men took the siblings along with Erica's 32-year-old boyfriend Jose Guadalupe Castaneda Benitez.
The witnesses said the armed men identified themselves as members of the Hercules unit and warned against intervening.
The father of the three Americans, Pedro Alvarado, later identified his children from photographs of the bodies showing tattoos.
Each person had been shot in the head and the bodies were burned - most probably from having been lying in the hot sun for so long, police said.
The siblings were last seen in El Control, a small town near the Texas border west of Matamoros, about to return home to Progreso, Texas.
"They were good kids," said an aunt. "I don't know why they did that to them."
The three siblings lived with their mother, less than three miles from the border.
Erica, who has four children between the ages of three and nine, had been due to begin studying to become a nursing assistant next month.
If confirmed, it will be the third recent case of alleged abuse and killings by Mexican security forces, and the first to involve Americans.