IGUALA, Mexico (AP) — Security forces investigating the role of municipal police in clashes in this southern city a week ago found a mass grave on the edge of town, raising fears the pits might hold 43 students missing since the violence that also resulted in six shooting deaths. 
 
 A Mexican marine guards the road that leads to the site where an alleged clandestine mass grave was found near the city of Iguala, Mexico, Saturday Oct. 4, 2014. Mexican officials said a clandestine grave... (Associated Press) 
 
 Mexican marines guard the road that leads to the site where an alleged clandestine mass grave was found near the city of Iguala, Mexico, Saturday Oct. 4, 2014. Mexican officials said a clandestine grave... (Associated Press) 
 
 State police guard the road leading to the site where an alleged clandestine grave was found near the town of Pueblo Viejo, Mexico, Saturday, Oct. 4,2014. The clandestine grave holding an undetermined... (Associated Press) 
 
 A Mexican navy marine guards the road that leads to the site where an alleged clandestine mass grave was found near the city of Iguala, Mexico, Saturday Oct. 4, 2014. Mexican officials said a clandestine... (Associated Press) 
 
 Guerrero State Prosecutor Inaky Blanco did not say Saturday night how many bodies were in the burial pits uncovered on a hillside on Iguala's outskirts, and he declined to speculate about whether the dead were the missing students. 
 
 "It would be irresponsible" to jump to conclusions before tests to identify the bodies, Blanco said. Officials said the federal Attorney General's Office and the National Human Rights Commission had sent teams of experts to aid state authorities in identifying the remains. 
 
 Guerrero Gov. Angel Aguirre said the victims had been "savagely slaughtered." 
 
 About 100 soldiers, marines and federal and state police cordoned off the area where the grave site was found in the poor Pueblo Viejo district of Iguala, which is about 120 miles (200 kilometers) south of Mexico City. 
 
 Blanco said eight more people had been arrested in the case, adding to the 22 Iguala city police officers detained after a police confrontation with student protesters last weekend set off a series of violent incidents in the city. 
 
 The prosecutor has said state investigators had obtained videos showing that local police arrested an undetermined number of students after the initial clash and took them away. 
 
 He said some of the eight newly arrested people were members of an organized crime gang, adding that some of them had given key clues leading to the discovery of the mass grave. 
 
 Blanco said his investigators had found that "elements of the municipal police are part of organized crime." He also said his office was searching for Iguala Mayor Jose Luis Abarca and had alerted officials across Mexico to be on the lookout for him. 
 
 The governor said had charged earlier in the week that organized crime had infiltrated the city government. 
 
 Jesus Lopez, the father of one of the missing students, told The Associated Press that a delegation of family and school representatives would come to Iguala on Sunday to get information from authorities. 
 
 "We cannot say anything. We are very nervous, but until they inform us, there is nothing," said Lopez, whose 19-year-old son, Giovani, hasn't been seen since the violence last weekend. 
 
 State prosecutors have said the first bloodshed occurred when city police shot at buses that had been hijacked by protesting students from a teachers college, killing three youths and wounding 25. A few hours later, unidentified masked gunmen shot at two taxis and a bus carrying a soccer team on the main highway, killing two people on the bus and one in a taxi. 
 
 Violence is frequent in Guerrero, a southern state where poverty feeds social unrest and drug gangs clash over territory. 
 
 The Aytozinapa Normal school attended by the missing students, like many other schools in Mexico's "rural teachers college" system, is known for militant and radical protests that often involve hijacking buses and delivery trucks. 
 
 In December 2011, two students from Aytozinapa died in a clash with police on the highway that leads to the Pacific coast resort of Acapulco. Students had allegedly hijacked buses and blocked the road to press demands for more funding and assured jobs after graduation. Two state police officers were charged in the shootings. 
 
 During that confrontation, students apparently set fire to pumps at a gas station on the highway when federal and state police moved in to quell the protest, and a gas station employee later died of burns suffered in the attack. 
 
 ___ 
 
 Associated Press writers Mark Stevenson and Maria Verza in Mexico City contributed to this report. 

 IGUALA Mexico (Reuters) - Authorities have found mass graves with the charred remains of up to 20 people in the restive southern Mexican state of Guerrero, at a time when police are scouring the area for nearly four dozen missing students after a rash of violence. 
 
 The remains were found on a hillside on the outskirts of the town of Iguala in six graves, which were still fresh, a local official said, speaking on condition of anonymity. 
 
 The identities of the dead were not immediately clear, two officials added. 
 
 Guerrero Attorney General Inaky Blanco told reporters in Iguala on Saturday that the remains would be sent to Mexico’s forensic service to determine whether or not the corpses were those of the missing students. 
 
 He declined to say how many graves or corpses had been found. 
 
 “In the next few hours we will determine the cause of death and the number of bodies,” a spokesman for the state attorney general’s office said. 
 
 Iguala is about 120 miles (193 km) south of Mexico City in the increasingly violent state of Guerrero, the site of clashes involving students, police and armed men last week. At least six people were killed in a spate of incidents. 
 
 Guerrero Governor Angel Aguirre said earlier this week that photos showed police had taken some of the students away. 
 
 Several hundred students protested on Saturday night in front of Aguirre’s residence in the state capital of Chilpancingo, expressing anger that some of their classmates may be among the bodies found in the graves. 
 
 A car was overturned and several petrol bombs were hurled at the residence perimeter, where security outposts were lightly damaged. 
 
 An police official said on Saturday that there was video footage of eight to 10 students being put into police trucks earlier in the week. 
 
 Twenty-two police officers were arrested in Guerrero on Sunday, accused of killing two students during the clashes last week. 
 
 Aguirre said on Saturday that a total of 30 individuals have now been detained in connection with the incidents. 
 
 Slideshow (5 Images) 
 
 Local government officials criticized the police for showing an excessive use of force with the students in Guerrero, where gangs have evolved from a fragmented drug cartel and are fighting turf wars. 
 
 Thirteen of an original group of 57 missing people re-emerged this week. Some had hidden, others had gone home. Dozens are still unaccounted for. 
 
 Many mass graves have been found across Mexico in recent years and months, the legacy of drug gang violence that has killed around 100,000 people since 2007.
– Mexican forces searching for 43 students who went missing last weekend amid violence in the southern state of Guerrero made instead a grisly discovery yesterday: Six freshly dug mass graves on the outskirts of Iguala city containing at least 20 bodies, reports Reuters; the victims had been "savagely slaughtered," as per Guerrero's governor. It's not clear whether the bodies in the graves are the missing students, notes the AP, with the state's prosecutor calling such speculation "irresponsible." "In the next few hours we will determine the cause of death and the number of bodies," his spokesman tells Reuters. Student protesters and police clashed last weekend, and six people were killed. State investigators say local police are shown in video hauling away some of the missing students; 22 officers have thus far been arrested, with the state prosecutor saying that "elements of the municipal police are part of organized crime." Eight other people he says are also tied to organized crime have also been arrested. Meanwhile, fresh violence broke out in the state capital last night, with protesting students overturning a car and lobbing gas bombs at the governor's residence.