Why does Mara, the Evil One one comes looking for consciousness at death? Is this explained in the Pali Canon?


  Then the Blessed One went with a large number of monks to the Black Rock on the slope of Isigili. From afar he saw Ven. Vakkali lying dead on a couch. Now at that time a smokiness, a darkness was moving to the east, moving to the west, moving to the north, the south, above, below, moving to the intermediate directions. The Blessed One said, “Monks, do you see that smokiness, that darkness …?” “Yes, Lord.” “That is Mara, the Evil One. He is searching for the consciousness of Vakkali the clansman: “Where is the consciousness of Vakkali the clansman established?” But, monks, it is through unestablished consciousness that Vakkali the clansman has become totally unbound.”— SN 22:87
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.