Should I pursue my termination legally

Hello, last year I was hired by the Eugene police Dept as an officer. I was recruited as the first non citizen officer in the dept. I was assured by the chief and recruiting lieutenant that this job is stable and I would not be terminated especially not for citizenship reasons. They said that they terminated some officers for egregious action only. When I accepted the position and started training, I noticed how conservative the general atmosphere was. It was uncomfortable but I was interested in the job. We started firearms training and I started to feel extremely harassed, yelled at, isolated on a couple of occasions for unsafe action. After the end of the training and not achieving a passing score, I was told that I won't be continuing as an officer. I was never told before that this was a fire-able issue and having had 0 experience in firearms I felt like that was unreasonable. I later learned that the dept usually gives trainees more time while I was not. I always felt like the training sergeant had a thing against me and suspected it was because my ethnicity, Middle Eastern, and putting all these things together made me conclude that they just wanted to get rid of me. Not sure if I should pursue this or not but I thought I'd ask.