What is the proper way to react to and deal with a fellow Jewish co-worker who has appeared to act inappropriately in a business matter?  I do not have 100% proof of inpropriety, and because of a lack of total proof I will not openly accuse. Acting inapproprately for money is a form of idolatry, while me being angry etc. can be considered to be as well, and can cause baseless hatred.

Hi, Thanks for asking this question.

My advice to you is to be the best Jew you can without worrying about this other guy. We all need improvement in our lives and we are all connected. If I see a fellow Jew doing something wrong it is my obligation to help him, but I also have to improve the world by improving my personal Judaism. I think that the real question here is what are you going to do to improve our national soul by improving your Jewish life? Of course, baseless hatred is forbidden, but the world can only be fixed through goodness, mitzvah observance, and doing the will of Hashem (G-d). You sound like the type of person who will make changes in his life in order to make the world a better place. Coming to Rosh Hashana this is the time and this is the opportunity that you need to improve our collective new year. Each week take a new mitzvah or a part of a mitzvah (mezuzah on another door, saying shema twice a day at the proper time, teffilin, praying, etc…) and add it to your Jewish life. That is how we Jews deal with anger. We improve our own lives.
Be Well, Rabbi Litt