Okay, so at the start in the town plaza, Theif V will turn fully around at the road before entering the east village. MAKE SURE you are on his LEFT , because he won't see you. Evertime he stops, you should stop too because you actually walk a little faster than him. At ALL times, you should be at least 5 cm ( 2 ft) away from him, otherwise he runs away and your left puffing. Now here's the tricky bit: at the falls, pass over the two logs and then at the walk up, left Theif V walk ahead. You must stop before the cliff face, otherwise an invisible block stops you from continuing on to see his lair, and he runs off again. This takes patience and time, so hopefully you were luckier than me and had to repeat it sooo many times. Good luck!