What happens to a no witness case?

depends on your case, if u r claiming that someone has done damage to your property and even though there is evidence of damage but did not see the person in actual action, then it's your Word against theirs. if someone claims you hurt them and there is no evidence of trauma/ any physical evidence or even that u attacked them, and only liable witness decides not to testify, its your Word against them. it's as simple as this i can say i don't know you, or know what u r talking about and u can say the same thing. why do u think cops help each other lie about being the other witness. because if there's no evidence to prove a cops case against you, then cops partner and back-up officers lie for cop claiming injury. whatever one cop say the other back it up.