Why does Mara, the Evil One one comes looking for consciousness at death?
In many cases Mara the Evil One appears when he realises that someone somewhere is about to escape from his grips, when they are practising ardently, about to attain enlightenment, and his purpose is to arouse fear, trepidation, and so on to disrupt their practice.Kassaka Sutta,Brahma-nimananika Sutta,Soma Sutta,Sister Vajira Sutta etc..

IMHO Mara is searching to see if Vakkali has actully escape from him. If Mara has to search, that means that that consciousness has already gone beyond his domain.