The Americas

Mexican official defends evidence in students' case

Family members of 43 missing teachers college students carry pictures of the students as they march with supporters to demand the case not be closed and that experts' recommendations about new leads be followed, in Mexico City, Tuesday, April 26, 2016. The U.N. Office of the High Commissioner for Human Rights said Tuesday that it is troubled by a group of international experts' complaints of obstacles to their investigation into Sept. 26, 2014 disappearance of the students in southern Guerrero State.(AP Photo/Rebecca Blackwell)

Family members of 43 missing teachers college students carry pictures of the students as they march with supporters to demand the case not be closed and that experts' recommendations about new leads be followed, in Mexico City, Tuesday, April 26, 2016. The U.N. Office of the High Commissioner for Human Rights said Tuesday that it is troubled by a group of international experts' complaints of obstacles to their investigation into Sept. 26, 2014 disappearance of the students in southern Guerrero State.(AP Photo/Rebecca Blackwell)  (The Associated Press)

The director of Mexico's criminal investigation agency is defending the handling of evidence in the case of 43 missing students, after an international group of experts raised questions about it.

Tomas Zeron says he visited the scene where charred bone fragments believed to belong to the students were found on Oct. 29, 2014. He acknowledges that he visited the scene Oct. 28, but he said Wednesday no evidence was picked up that day.

The group of outside experts had questioned why an investigator was seen picking up a bone earlier, and at a different site, than investigative records suggest.

Zeron said the bone belonged to a bird.

The experts and the victims' parents question the government's version that the students were killed, burned and their bones dumped in a river.