Families of dozens of Mexicans students, who allegedly went missing last week at the hands of the police, have joined the search being conducted by around 160 state security officials.

The students went missing after municipal police and unidentified gunmen attacked them in the southern city of Iguala. Six students were killed and eyewitnesses say local police arrested many, but none have turned up in detention centres. Authorities suspect that they may have been handed over to drug gangs who operate in the area.

Al Jazeera's Rachel Levin reports from Iguala.