Mexican authorities have found four more mass graves containing charred bodies in the south west of the country where 43 students went missing two weeks ago.

The search for the fugitive mayor of Iguala and his wife is now formally underway, and new arrests were made in the investigation.

“We have four new detainees whose identities are being confirmed which is why I will not give names yet, but the most important thing is that with this arrest they were able to take us to a place where we found four mass graves, which these detainees said were also where the remains of the murdered students were deposited,” explained Jesus Murillo, Mexico Attorney General.

DNA samples were being taken from the relatives of the missing students in order to make a positive identification.

Thousands demonstrated in the Mexican capital to pressure the government to get to the bottom of the matter, which many believe involved gang members and police.