Landmark police trial in Nigeria

Nigeria's police have a history of violence

The trial of six police officers in Nigeria charged with the murder in June of six traders has open in the capital, Abuja, amidst heavy security.

It is the first time that senior officers have faced trial and they could face the death penalty.

The police say they killed the traders in self defence when they failed to stop at a check point.

But riots in the traders' home village of Apo, near Abuja, led to a public outcry and a government investigation.

The BBC's Hindu Waziri in Abuja says Nigeria's police have a history of violence and extra judicial killings - but none have gone to trial due to a lack of evidence.

Disappearances while in police detention are not uncommon, she says.

Five of the six accused police officers were in court on Monday and include an assistant police commissioner who is the most senior official to be charged with such a crime.

The men pleaded not guilty.

The sixth accused is still at large.

The trial has been adjourned until Wednesday.