i think gug did it because

one one of them is lying

now if GUG is lying (meaning someone else is telling the truth) then that means that he did it

if gug is telling the truth then that wud mean

dave says tony did it...(but he's lying) meaning tony did not do it

tony says that dave is lying when he says that tony did it (since he's lying too) meaning that dave is telling the truth meaning that tony did it

since this is a contradiction... this is not possible

any suggestions??

hi friends

answer is dave did it

because only one is lie consider dave lies

then all other statement becomes true

else anyone ll contradict with condition