Three quarters of Yemen's population live in rural areas, many of which are under the authority of local sheikhs rather than the government.

It has led to a culture of private prisons where arrests are often made at the will of the powerful sheikhs.

Inmates have little legal recourse and cases of torture and even execution are not unheard of.

Al Jazeera's Mohammed Vall reports from Yeman. (12 Jan 2010}