Mario Alvaro Cargajena Lopez says his leg was amputated during five years of torture

And for the first time he has appointed an official - Dr Mario Ignacio Alvarez Ledesma - to oversee human rights within his own office.

Together, human rights agencies say they mark a significant admission by the attorney general that a serious problem of torture exists.

"Many violations of human rights, and in particular torture, happen because the officers don't have adequate training," said Dr Alvarez.

"Unfortunately they resort to torture to get the information, or confession that they want because it's the only way they know.

A professional policeman doesn't have to use torture to do his work," he said.

Course aim

The course is aimed at police prosecutors - the officials who deal with alleged offenders after they have been arrested.

It teaches them the limits of what is and is not appropriate treatment of suspects and how to recognise the signs of abuse when police have gone too far.

Does it count as torture if there are no physical marks?

Policeman

The course notes cover the legal definition of torture, international conventions concerning torture, and the physical and psychological symptoms of torture.

According to the notes, the main object is to "promote a culture of fundamental rights and in particular, an awareness among [Justice Department] officials that the phenomenon of torture runs counter to the procurement of justice."

One lecturer - a human rights lawyer - dissected the law for his audience.

"The inflicting of wounds, mutilations, burns, pain, physical or psychological suffering, is a violation of the penal code," he said.

"The text doesn't specify that it has to be serious. Any form of abuse is too much."

Move welcomed

To many in the course, the news came as a surprise. "Does it count as torture if there are no physical marks?" asked one participant. "And how do we know if the marks that they do have were sustained in the police cells?"

Human rights organisations have welcomed the move, but they argue that it will take a good deal more than a simple course to deal with the problem.

"This has been going on not just for years but for decades," said Rosario Ebarra de Piedra of the Committee for the Defence of Political Prisoners, Exiles and the Disappeared.

To underline their point, the committee staged a demonstration on Mother's Day outside the president's offices in the Zocalo square in the heart of Mexico City.

Deeply entrenched

Standing behind a banner with the faces of the disappeared, Ebarra de Piedra said they chose the day to emphasise that while most people were celebrating, for relatives of the disappeared Mothers' Day was a sharp reminder of the damage the authorities had done to families across Mexico.

"The course is a start, but the people who've been doing the torturing all this time are still there, sometimes in positions of real power.

A mother holds a photo of the daughter she says disappeared in police custody

"Nothing can change until all those people have been removed and punished."

Dr Alvarez from the attorney general's office conceded that much more needed to be done, but he insisted the government is well on the way to tackling the problem.

"We can't do this overnight, because we recognise that this is a huge structural problem.

"We need to professionalise the police force; we need to change the structure entirely so that corruption is eliminated; we need to raise wages; and we need to re-educate our officers so that they understand that times have changed."