Thank you for sharing this horrid story with us theREALjLo, very brave of you and appreciated!
The combination of tracksuit with dress shoes and briefcase is a key clue I think.
Perhaps he changed out of his work clothes to conduct his attack with the intention of changing back into his original clothing afterwards. So his work clothing would not get torn, dirty etc.
Therefore perhaps commuted in work clothes, briefcase and dress shoes from Edgewater train station on a daily basis and lived near area]
I agree with the clothes being the key. I see it moreso as a disguise of sorts though, for someone who has never had the need to wear dress shoes or carry a briefcase. My guess is he was hoping that from a distance, his tracksuit would appear to be a suit so any reports or sightings would be made with the description being a businessman. Id be inclined to think the briefcase was empty and the fact he would have to drop it at some point in an attack, thus increasing his risk of having to flee without was probably something he didn't think too much about.