Check this out, I'm going to help you learn anything you want. Take note that you can do this for any subject.
Often when you can make sentence that goes "I want to find (something)" You can go to a search engine (like this one www.google.com , but there are other ones which don't invade your privacy if that is a concern), and then type that something directly into it.
So go there, and type in "comprehensive academic level "theory of sin""
The first 5 results are a Calvinistic view on the subject, a systematic theology break down by Berkhof, Augustine's view on sin compared with an eastern view, an angelican document, and then some guys blog. Refer to picture 1.
This will then help you refine your search, because these might not be exactly what you want. But it gives you a good starting off point if they are.
Next, go to wikipedia. Find the topic you are interested in. Since the entry is supposed to be a sort of summery of the topic, that will help you identify that this is what you are looking for. In this case, this seems to be what you are looking for.
https://en.wikipedia.org/wiki/Christian_views_on_sin
Now clearly you want something more in depth. So here is what you do, you go down to the bottom of the page and look at the sources for the entry itself. Refer to picture 2.
Some of the footnote references only give a name, these entries correspond to the works listed in the bibliography.
There are also external links that can often take you exactly to that material itself. In this case, works by Augustine or Aquinas. In this case, the link to Aquinas is actually EXACTLY what you are asking for in this case, going in depth as to the nature of sin itself. A good many Christian hold the same view as he does on this matter.
Now, if that doesn't satisfy you, you have loads of other leads to follow. You can go to any other of the works listed and look through them if you want. Or refine your search.
I hope this helps.