Oh, there are masses of online sources where you can look freely into statistics, details, documents, testimonies and more.
Now please READ this post before fisking it. Read ALL of it to the end. And the next post.
I would suggest you start with Yad Vashem and digest every single article/document/source that is available on their site. The Holocaust Resource Center has numerous documents, articles and other items
http://www1.yadvashem.org/yv/en/holocaust/resource_center/index.asp
The index for Righteous among Nations, for example, includes the following
Total Sources (by media type):
Artifact Collection 28
Diaries and Letters 1
Documents 1
Lexicon Entries 64
Photographs 45
Research 8
Testimonies 7
Works of Art 1
Total Sources 155
This category will provide masses of information about how some few Jews survived, how they avoided detection, and by implication how others were caught.
Another category is 'the Local Population', divided into several sections.
One section deals with 'perpetrators and murderers'
The same information is available on Wikipedia in condensed form; careful surfing and following of links will arrive at the same results.
And there are also independent websites discussing the same issues. One
archived site is called 'Saving Jews' and deals with Poland.
The thing you'll have to get over pretty rapidly is looking for a
single source since you are dealing with events that took place on the territory of 25 contemporary nation-states. It has been obvious since the 1940s that events unfolded differently depending on the territory in question, because of differences in culture, politics, economics, social structure, wartime conditions, and the degree of ideological fervour of the occupying Nazis or their local pro-Nazi collaborators, as well as the background level of antisemitism.
I gave some examples from France, Belgium, the Netherlands and Poland up-thread. Obviously, each of these countries has its own encyclopedia entries, its own websites dedicated to the issues involved, and its own scholarly literature.
For example, the basic facts about the Holocaust in the Netherlands are summarised perfectly accurately in
Wikipedia's entry on the history of the Jews in the Netherlands. The entry gives some perfectly decent online web pages as sources, which in turn refer to other sources, which in turn refer to primary sources. That's just how the world is with any subject in history.
Or you can continue googling, and will come across other sites, with the caveat that a lot of stuff isn't going to show up in an English keyword search, because duh, the sources will be in Dutch.
If you ask nicely, our Dutch members here - there are several participating in the discussion -will direct you to various sites, sources and materials about the Holocaust in the Netherlands. The Dutch research institute NIOD has scanned large amounts of documents from Westerbork which document the deportations; there are demographic studies, studies showing variations in the regions, and one can also read the standard work on the Holocaust in the Netherlands by Jacob Presser online, in Dutch.
Alternatively, you can simply order Bob Moore, Victims and Survivors, and get a really good summary of all the issues.
Or, you can order Raul Hilberg, The Destruction of European Jews, in any edition other than the student edition (which is overly condensed), and read his chapter on the Netherlands, and also read the chapters on other countries, since Hilberg gives very good summaries of the bureaucratic procedures involved.
By this stage, you should have realised that the Nuremberg records, in addition to the Eichmann trial records, are online, and since these contain a very great many answers to your questions, they can be read, too.
You really have two choices. One, you can reconstruct the massive research effort of others yourself with free materials, or two, you can order a few books from a library or bookshop, and benefit from the fact that you are asking questions which have pretty much already been answered. The freebie route will take a little longer.
Either route requires careful study and the use of multiple sources.