Forty-three Mexican students who went missing six weeks ago were likely abducted by police and handed over to a local gang who murdered them and burned their bodies, Mexico’s attorney general said Friday.

Attorney General Jesus Murillo Karam said three members of the Guerreros Unidos gang were apprehended last week and confessed to burning a number of bodies near Iguala in the Guerrero state in an effort to remove evidence of the killings.

READ MORE: Mexico’s missing students: New mass grave uncovered

"They didn't just burn the bodies with their clothes, they also burned the clothes of those who participated," Karam told a news conference. "They tried to erase every possible trace."



"I know the huge pain this information gives the families, a pain that we all share in solidarity," he added.



The victims were young male students from an all-male liberal college in rural Ayotzinapa. On September 26, the students arrived in the city of Iguala where they planned to stage a protest over a lack of government education spending. Following a clash with police, 43 members of the group disappeared.

Karam presented videotaped confessions by the murder suspects that included a segment showing charred bits of bone and teeth dragged from the San Juan River in Cocula, a town near Iguala.



Authorities announced Friday they had discovered six bags of unidentified human remains along the river’s bank.



In a telling testament to the violence now proliferating in Mexico, the district attorney noted that human remains found in hidden graves after the students went missing were not those of the 43 young men.



Karam said the abductors questioned the students about their alleged membership in other gangs, adding there was no evidence to support the claim the missing students were involved in gang activity.



The attorney general said the government was carrying out DNA tests to confirm the identity of the bodies, a process that he said “will be a challenge” due to the badly burned fragments available to forensic experts. The remains would be delivered to the University of Innsbruck in Austria for concluding DNA identification, he added.



"I have to identify, to do everything in my power, to identify, to know if these were the students," Murillo said.





Meanwhile, more details are emerging in the shocking story that has stunned Mexico, a country that is no stranger to violence, much of it drug-related.



This week, authorities arrested Iguala Mayor Jose Luis Abarca, who is believed to have ordered the abduction of the students, and his wife, Maria de los Angeles Pineda. Investigators say the mayor ordered his police chief Felipe Flores Velasquez, who remains a fugitive, to prevent the student protest in the city.



To date, 74 people have been arrested in connection to the case, authorities said.



Meanwhile, the parents of the 43 students have been highly critical of Mexican President Enrique Peña Nieto, who they say didn’t do enough to track down their missing children. The lingering frustration after weeks of failed efforts to find the students has fueled protests and even violence across the country. This week, thousands of demonstrators marched on the capital, Mexico City, to protest the government’s response to the incident.

READ MORE: Furious students burn Mexican govt. building in protest over police corruption

Peña Nieto, who was elected two years ago after pledging to tackle gang-related violence, promised that justice would be served.



"The investigations will be carried out to the full, all those responsible will be punished under the law," he said.



"The capture of those who ordered it isn't enough; we will arrest everyone who participated in these abominable crimes."



About 100,000 people in Mexico have lost their lives in violence related to organized crime since 2007.