The acting Speaker of South Sudan’s Council of States, Mary Ayen Majok, has urged authorities to urgently accelerate investigations into the killing of opposition legislator Luka Mathen Toupiny Luk, who was shot dead in Juba.

In a condolence message released on Monday, Majok described Mathen’s death as a serious national loss and called on security agencies to ensure that those behind the crime are swiftly identified and prosecuted.

She said the leadership of the Council of States was appealing to “relevant authorities to fast-track investigations, bring the perpetrators to justice and ensure accountability for the murder of the late Luka Mathen.”

The 36-year-old lawmaker was attacked by unidentified gunmen near his residence in the Gudele neighbourhood of Juba at around 10pm on Saturday, according to family members and colleagues.

Police later confirmed the arrest of two suspects in connection with the killing but declined to release further details, citing ongoing investigations.

Mathen represented Cueibet County in Lakes State in the Council of States, South Sudan’s upper legislative chamber. He also chaired the specialised committee on education, science, research and technology.

Majok described him as a committed and hardworking public servant, noting that he would be remembered for his effective oversight role and contribution to national development.

“His passing is a profound loss not only to his family and the people of Lakes State, but to the entire country,” she said, adding that the Council of States stands with his family during the difficult time.

Mathen was a member of the United Sudan African Party (USAP), which is part of the Other Political Parties (OPP) coalition, a signatory to South Sudan’s 2018 revitalised peace agreement.

He joined the Council of States following the 2018 peace accord and previously served as a court clerk before entering national politics.