Mexican authorities searching for 43 missing college students have found human remains and are testing to see if they belong to the young men who were last seen in police custody a month ago.

Authorities testing remains found in nine mass graves in southern Mexico have yet to find any of 43 students who disappeared after a confrontation with police.

Soldiers dug through tons of mud and dirt in search of victims of a massive landslide, as Mexican authorities looked for a police helicopter that went missing while carrying out relief operations on the flood-stricken Pacific coast.