Bahrain has been criticized by international authorities and rights groups for abuse of prisoners and protesters by police. In April Human Rights Watch reported that Bahrain's police officers regularly abuse minor detainees [JURIST report] before transporting them to police stations. Other rights groups have made similar allegations concerning police brutality in Bahrain. Earlier in April Amnesty International issued its own report [JURIST report] alleging human rights violations continue in Bahrain despite reforms. Also in April four independent UN human rights experts called for the immediate release of Bahraini human rights defender [JURIST report] Abdulhadi Al-Khawaja, who is serving a life sentence for terrorism-related charges after being tried before the Bahrain military National Safety Court in June 2011. Special Rapporteur on human rights defenders Margaret Sekaggya expressed concern that Al-Khawaja's trial and sentence are linked to his legitimate work to promote human rights. Last year a Bahrain court sentenced four protesters to death [JURIST report] for their roles in the killing of two police officers committed during mass anti-government protests. Three others were sentenced to life in prison.