i work for a tribe in colorado and there is three employees that harrass me and verbally abuse me. My boss is not aware of it and when reported does nothing about it. I want to record conversations on the phone and in person. I would like to hide it but d

Abuse of power in positions that are subordinate to mine.
When boss is gone the women verbally try taking over my position and threaten me with write ups and becoming my supervisor.
My supervisor did nothing when confronted after his return. Now I am documenting and going up the chain of command but I want evidence of how they speak to me. I work for the Southern Ute Indian Tribe and am a tribal member. Two of the three people are not tribal members. Also one is a subordinate and one is an equal. I am dealing with extreme politics but need to know legally. I have evidence of recent events but they are still almost hearsay events for the most part. Can i record with their knowledge by bringing out a tape recorder. Can I do it without their knowledge?