This seems more like prose than poetry, although it is broken into lines. I feel like since you began each line with a capital letter you should end with punctuation. It just does not feel quite right as it stands. The point of this poem seems to be that you do not really know the people walking by you as you go through your life. You tend not to even see them. I think the idea of one of them being a killer is kind of a downer. perhaps you could add another more positive possibility like them being a volunteer at soup kitchens or an off duty paramedic. It would balance out the negativity a little. or if you want a darker tone to the piece give another example of a dark secret like spousal abuse or something.