Forum:How to kill the master of thieves?

first: hi i'm new here and i just started playing Nethack(nethack-qt on linux)

my friend has a tourist lvl 26 in Home 3 "battling" the master of thieves as part of the tourist quest.

here's his problem, every time he hits this guy he vanishes (after hitting him 3 times in a row) only to reappear several steps later, so how does he kill/defeat him and get the credit card?