The United Nations Support Mission in Libya called Sunday for an investigation into a political activist’s death while detained at an eastern military base controlled by General Khalifa Haftar’s forces. UNSMIL also demanded the “immediate release” of other prisoners it said were being detained “arbitrarily” by the war-torn country’s eastern-based authorities. In a statement on X, the UN mission said it was “deeply saddened by the death of activist Siraj Dughman while in custody at Rajma military camp” and urged the Libyan “authorities to conduct a transparent and independent investigation into…