Sixteen suspects in the murder of a Christian secondary school teacher in the northern Nigerian state of Gombe, have been released without charge. The decision has caused dismay in local Christian circles.

Married mother of two, Christiana Oluwatoyin Oluwasesin, was brutally murdered on 21 March 2007 after a Muslim student falsely accused her of having torn a copy of the Quran. The student had been caught cheating in an exam at Gandu Government Day Secondary School.

Mrs Oluwasesin had confiscated a paper with Arabic inscriptions which the student had hidden in a book. Despite another teacher showing that the book was not the Quran and had not been torn, a mob of students attacked Mrs Oluwasesin, Christian Solidarity Worldwide (CSW) has reported.

They were aided by residents from the surrounding area who had been drawn to the scene by the clamour. She was stoned, stripped, beaten, and stabbed to death, and her body was later burned beyond recognition.

Local observers believe the incident may have been pre-planned. Two weeks prior to her death Mrs. Oluwasesin was targeted by thugs whilst in the local town and had to be rescued by passers-by. The attack that ended her life lasted for an hour.

According to the findings of a report commissioned by the Gombe Chapter of the Christian Association of Nigeria (CAN), a notorious member of a local gang of Islamic militants, nicknamed the 'Angel of death', arrived at the scene on the back of a motorcycle as the victim knelt begging for her life. He slit her throat and stabbed her in the stomach and breast before the students set her body on fire.

CAN Gombe investigators also discovered that four policemen armed with guns and teargas were in the school grounds when the violence began, but ran away from stone-throwing students without firing weapons to disperse them and without calling for reinforcements.

Although the students set fire to classrooms, Mrs Oluwasesin's car and the motorcycle of another Christian teacher, local fire service personnel claim they could not reach the area as all roads were blocked by unspecified groups.

The report concluded that the school principle was the only person to offer any assistance to Mrs. Oluwasesin. He attempted to shield her with his body, and was badly beaten as a result.

The decision to release all of the suspects has alarmed the Christian community. Several fear that a high-level cover up may be underway after the state's attorney general went on air to claim that the suspects had "no case to answer". Some predict an increase in similar attacks if Mrs. Oluwasesin's attackers are allowed to go unpunished.

After killing Mrs. Oluwasesin, the crowd was heard chanting the names of other Christian members of staff and asking of their whereabouts, indicating that they too were being targeted.

In a statement to the governor of Gombe, the Christian teachers stated: "This implies that the massacre is not over; up to this moment some Christian teachers are being harassed on their way to their houses; hence our lives are still in danger".

CAN Gombe has called for the prosecution of the student involved in the initial incident, the man known as the 'Angel of death' and the school's head prefect, who has refused to reveal the names of others involved in the murder.

The organisation has also called for an investigation into the lack of police intervention on behalf of Mrs. Oluwasesin. So far several petitions by Christians to government authorities have not received a response.

Christian Solidarity Worldwide's National Director, Stuart Windsor, says: "This brutal murder of an innocent woman demands justice, and it is vital for the future of a unified and democratic Nigeria that no-one is considered above the law. The fact that this incident occurred in a federal institution is particularly disturbing.

"We therefore call on the incoming federal government to ensure that the authorities in Gombe take decisive action against the perpetrators of this gruesome act, who continue to harass Christian teachers in the state, and to work to end the culture of impunity in which such sectarian violence has been allowed to thrive."