You'd Never Guess

When mysterious robberies are going on around town, a group of teenage friends get together to investigate.
The aren't taken seriously until they crack a case. Then, one of the group is murdered, as well as others in their town.
The real outlaw is right within their group, even if they don't know it. The outlaw goes on to kill everyone in the group-except one. The second to last to die gives the one remaining (besides the secret killer and robber) a clue as to who the killer is. The not-dead one wants to bust the killer and robber, but can't, as romantic feelings take over. How will this end?