Mexico insists 43 students are dead
Mexico's attorney general says he can prove what happened to 43 students who disappeared in the southern state of Guerrero in September, the BBC reported.
Jesus Murillo Karam said his team had interviewed 99 people including members of the criminal gang whom he alleges murdered the students.
His comments come a day after relatives of the students marched in Mexico City.
They demanded government action and concrete proof of what had happened. four months after they disappeared.
Mr Murillo Karam insisted that the students were killed by a criminal gang and their bodies burnt at a rubbish dump - an explanation which has been rejected by the relatives of the disappeared.
He said his team had 39 confessions from police and from members of the criminal gang.
Correspondents say it is the first time Mr Murillo Karam has declared all of the students dead.
The remains of only one student have been identified so far after badly burnt bones were sent to a laboratory in Austria for DNA analysis.
The laboratory said it was impossible to identify any others because of the bad condition of the remains.