(CNN) A New Zealand nurse kidnapped by ISIS while working in Syria in 2013 may still be alive, the International Committee for the Red Cross (ICRC) revealed Sunday.

Louisa Akavi, 62, and Syrian ICRC drivers Alaa Rajab and Nabil Bakdounes, were abducted while delivering medical supplies to Idlib, in northern Syria, in October 2013. Four other members of the convoy who were abducted by ISIS were released.

The aid group had kept Akavi's name secret in a bid to keep her alive, working behind the scenes to try to secure her release.

The ICRC said its last "credible information" regarding Akavi's well-being came in late 2018, but it had never been able to ascertain the fates of Rajab or Bakdounes.

Dominik Stillhart, director of operations for the International Committee of the Red Cross, said that the organization believed that she continued to provide medical care, even while in captivity.

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