What do you think of the begining of this?

You have a good start to your story. Some of the words you use however could be stronger you need to keep the readers interest and keep them focused on the storyline. There should also be a sense of urgency in that this is a serious matter. Some scenes for example the phone scene drag on a bit too long. Also if your character has an idea like when you talked about the theory it does not fit unless you give the reader at least a small clue regarding what your theory is. Maybe you start to explain it and are interrupted by the phone. The way you explain it now disturbs the flow of your story. The last part is a bit wordy and not necessary for the reader you could start a new chapter and discuss a noise you hear while you are in the closet. I don’t know where you plan to go from here on the story but I hope this helps a bit. I have made a few suggestions and re-worked the writing a bit I think it would be helpful for you to go over it but I am unable to post it here. If you would like to look it over please email me and I will send it to you lecialoo@yahoo.com