How do I deal with a shady and suicidal roomate?

How do I deal with a room mate who says she’s suicidal or going to kill herself ?

I’m kind of worried about my room mate. She’s 36, single, does trade shows/ stand in work, and has a therapy dog.

This is only my 4th month living here with her, it’s a 2 bedroom 2 bathroom apartment in Los Angeles.

We had a 3rd roomate ( a guy ) who was renting out an enclosed part of the living room. He moved out around the beginning of the month of January.

He recently moved out but he had some of his mail still come to our place. On Friday his mail came in and I left it on the kitchen counter for the entire weekend. He said he could come by Sunday evening to pick up his mail that had an important check in it. My roomie (the one that says she’s suicidal) came home on Sunday night and took his mail…... I guess she threw it out, took it, threw it in the trash…. Who knows what she did with his mail…... As soon as she got home his mail that was sitting on the kitchen counter magically disappeared…..

He was already on his was Sunday. He came to our place asking where his mail went. I confronted our roomate and she said she put it in the outbox by the fountain in our apartment…... She starts yelling and screaming that she’s going to call the cops. She says she doesn’t have his mail and it’s “return to sender”.... So we ask her where she put his mail. She said it’s in the outbox by the manager’s…...

Then later one she says she put it in an outbox by a Gelson’s (a grocery store here in LA)..... So she lied about where she put his mail. She also said that if he killed her dog she would commit suicide…....... I have no idea why she would say that, no one cares about her dog….... Anyway, during this entire incident she’s sending me text messages saying she’s going to commit suicide…....

I am still here living with her but now it’s very awkward.

I don’t feel safe around her because I don’t know if she’s taken or stolen anything of mine…. I don’t want her to steal or take my mail. He said the she has over $1,000 of his checks….... That she’s been keeping or just throws it out…..... We think she had a crush on him then threw out his mail out of spite….. but my point is that I don’t feel safe around her. She acted like a psychopath screaming, yelling, etc. What she did to our old friend / roomate is extremely shady, mean, etc….. and I also thought that tampering with someone else’s mail was illegal???

I was friends with her first but I’m not anymore because I believe what she did to him was wrong and not cool at all. Who does that? Who takes someone else’s mail out of spite and throws it away??? She mentioned about me having a door on my lock… I don’t feel safe if I don’t have a lock on my door. I don’t know if she’ll go through my mail or steal my things.

Anyway, I just want to know how can I deal with this situation? I’ve been pretty much just ignoring her and doing my own thing.