Mexico's attorney general Jesus Murillo Karam has stated he can now prove the fate of the 43 missing students who disappeared in the southern state of Guerrero last September.

Karam and his investigative team interviewed 99 people, a number which includes members of the criminal gang that the attorney general alleges executed the students, and he has come to the conclusion that all of the students are dead, BBC reports. He added his team had the combined confessions of 39 police and gang members.

According to Karam, the students were murdered by the drug gang, and their bodies were then burnt at a trash dump.

The remains of only one student, Alexander Mora Venancio, have so far been identified. The ashes of his recovered chared bones were sent to a lab in Austria for DNA analysis. The lab, however, was unable to identify any other bodies due to the terrible condition of the remains.

The sobering information that Karam has brought forth is based upon the declarations of 386 interview subjects, 16 police raids and two crime scene reconstructions.

A key witness, according to Karam, was Felipe Rodriguez Salgado, a member of the drug gang who is alleged to have played a role in the kidnapping and murder of the missing 43 students.

"The evidence allows us to determine that the students were kidnapped, killed, burned and thrown in the river," Karam said.

Karam cited  gas, diesel, and burnt rocks and steel from the inside of tires that were placed at the scene of the crime as evidence.

Families of the missing students have said that there has been an absence of conclusive forensic evidence, and they have subsequently reacted with anger at the news that the investigation is off, stating that without proof they will continue to believe that their children are still alive.

Vidulfo Rosales, the lawyer who represents the families of the missing 43 students, has offered a 10-point argument explaining why the police should continue its investigation.