I think you can do better than "a man". He's your protagonist after all. Can you give us a little more so we get some idea of who he is and what his arc is. I'm guessing it's being able to let his wife go at the end?
I agree with Richiev about the structure - the police stopping the investigation is the inciting incident.
I think there's a big difference in saying "becomes [a] vigilante" and "fixes the suburb she loved". The latter is infinitely more powerful. Also, Richiev makes a valid addition in including his goal after he becomes a vigilante. Your logline doesn't really get us past the first act - what does he specifically want to do as a vigilante? I refer back to the "fixing the suburb she loved" bit. This doesn't fall into the Thriller genre as much as "catching his wife's killer".
I feel like the seeing his wife's ghost feels disconnected to the plot and again, I got a lot more information from the text under the logline. Is it a delusion or is he actually seeing her ghost?