TRIPOLI: The UN mission in Libya urged authorities on Saturday to open an investigation into the death of a prominent activist who prosecutors say threw himself down a stairwell after being detained.

Abdel Monem Al-Marimi was a well-known government critic and took part in regular protests demanding the removal of Prime Minister Abdulhamid Dbeibah.

In a statement, the UN Support Mission in Libya (UNSMIL) said Marimi “was reportedly abducted by the Internal Security Agency in Surman (west of Tripoli) on 30 June and referred to the Attorney General’s office on 3 July,” adding he later died under “circumstances that are yet to be clarified.”

According to local media, the activist died Friday night at a clinic in Tripoli from injuries sustained in a fall at the attorney general’s office.

The office has said that Marimi was taken to hospital after jumping down a stairwell.

The government has so far offered no further comment on Marimi’s death.

UNSMIL called for a “transparent and independent investigation into his arbitrary detention, allegations of torture during his detention, and circumstances surrounding his death.”

The attorney general’s office said that before the incident in the stairwell, Marimi had been released from an interview, adding it was reviewing surveillance camera footage.

UNSMIL went on to condemn “threats, harassment, and arbitrary arrests targeting politically active Libyans,” and urged the authorities “to uphold free speech and end unlawful detentions.”