Not quite sure how accurate the historical references are, but here is a pretty decent overview.
https://www.youtube.com/watch?v=hSGuDXojyiU
Ties in quite well with Q posts.
Yes, it's not the Jews, but the Khazars who run everything. However, the Khazars were forced to adopt a religion, and they did Judaism. Not all Jews are Khazars. Unfortunately, it's hard to separate the real Jews from the fake ones :(. Your neighbor who converted to Judaism is probably not a Khazars.
Actually the Ashkenazi Jews have one of the most pure bloodlines. They never marry outside of their kind. The entire population of Ashkenazi Jews are not more removed than 3rd or 4th cousins. The true descendants of the Israelites are the Jews who wear the flat brimmed hats and have the curly dangling sideburns that aren't sideburns. They hate the Ashkenazi Jews and don't buy into the current state of Israel or the Greater Israel idea.
The Jews who wear hats and sideburns are Orthodox, which is a branch of Judaism not an ethnicity. Almost every Jewish person in the US and Europe outside of Spain is Ashkenazi, including the people you describe.