Mexican authorities have passed clothing that belonged to some of the 43 students missing from rural teachers' college to a lab in Austria for genetic testing.

The attorney general's office said in a statement Tuesday that it sent some 53 items to the University of Innsbruck almost a year after the students' disappearance.

The announcement came after a panel of independent experts working under the auspices of the Inter-American Commission on Human Rights criticized the government's investigation for not testing the items or informing the students' families that they existed.

According to the government, the 43 students from the teachers' college in Guerrero state were seized by police in Iguala on Sept. 26, 2014. The police turned them over to a drug gang that killed them and incinerated their remains.