Mexican authorities say an Austrian laboratory has not found evidence that can confirm that remains found in a trash dump in the southern state of Guerrero belong to 43 students who disappeared in 2014.

The Attorney General's Office says the Institute of Legal Medicine at the University of Innsbruck examined samples including hair and physical remains. It said in a statement late Friday that it was not possible to establish genetic profiles at this point, and further testing is still being done.

Mexican investigators have said that police delivered the students to drug gang members who killed them and incinerated the bodies in a trash dump.

That finding has been disputed by two outside groups of experts who have examined the case, as well as relatives of the students.