A family member and a colleague said on Tuesday that Alieu Momar Njai, who served as the chairman of the Gambia's Independent Electoral Commission, had left the country for an unidentified place.
The escape comes a little over two weeks before the Gambia is to inaugurate President-elect Adama Barrow. The former real estate agent defeated Jammeh by a marginal difference in the December 1, 2016 election.
After the election, Njai faced criticism by Jammeh, who initially accepted the defeat but said later that he would challenge the results due to some inconsistencies in recounts.
Njai rejected Jammeh’s worry about the validity of the revised outcome and said the veteran leader, who first seized power in a coup, would go nowhere by challenging the outcome.
On December 13, forces loyal to Jammeh raided the office of the electoral commission and confiscated the property.
Jammeh has shunned international calls for a peaceful transfer of power in the Gambia.
The Economic Community of West African States (ECOWAS) warned that they could use military power to push Jammeh out of office. Jammeh called that decision a "declaration of war" and accused the African leaders of trying to undermine the sovereignty of the Gambia.
"Let me make it very clear that we are ready to defend this country against any aggression ... My government will never opt for such confrontation but defending our sovereignty is a sacred duty for all patriotic Gambians," he said in a New Year speech.