UN rapporteur for human rights is set to arrive in Turkey on Monday to investigate the case of Saudi journalist Jamal Khashoggi, nearly four months after his murder inside Riyadh’s consulate in Istanbul.

Agnes Callamard, the UN’s special rapporteur on extrajudicial, summary or arbitrary executions, was scheduled to be in Turkey until February 3 to collect findings on the death of Khashoggi, ahead of a June meeting of UN officials.

The visit comes on the heels of Saudi efforts to normalize ties with the international community that has questioned the credibility of Riyadh’s probe into the Khashoggi murder.

Saudi Arabia insists that the death of Khashoggi, a Saudi national and vocal critic of Crown Prince Mohammed bin Salman, was a “rogue operation” and has put 11 defendants on trial for the crime.

However, Turkish President Recep Tayyip Erdogan has insisted that the order to kill Khashoggi came from the highest levels of the Saudi government.

Foreign Minister Mevlut Cavusoglu has called for an international probe and that Erdogan ordered for preparations to this end, according to state news agency Anadolu.

UN Secretary-General Antonio Guterres previously said he does not have the authority to launch an investigation into the death of Khashoggi and no country had submitted an official request to launch a criminal investigation.

The UN team will now assess steps taken by Turkish and Saudi governments to address the case, Calamard said in a statement on the UN’s human rights branch website last week.

The UN experts will also assess the “nature and extent of states’ and individuals’ responsibilities for the killing,” the statement read.