In the Mexican state of Guerrero, more than 50 students from a teacher training college have been missing since Friday night following violent clashes with police. According to human rights groups, police and unidentified gunmen opened fire on students in separate incidents near the city of Iguala, killing at least two and leaving one in a vegetative state. A third student was reportedly found dead with signs of torture. More than 20 police have been detained in connection with the incidents. The scores of missing students include many detained by police and others who scattered during the violence.