My son is in a dangerous situation right now with his girlfriend

My son is 17 and his girlfriend is 19. They've been dating for 2 years. Last year she got involved in a gang but got out months later. However she's had to change her phone number multiple times because she's been getting stalked. My son tells me everything and he told me someone is trying to kill her. I asked why and he told me that he can't tell me that much info. I told him i don't think it's safe for him to be around her and he told me that isnt fair at all. Last week I overheard him on the phone with his friend. He was driving her home from work and someone was following him. So he drove his car into a public parking space and sat there for a while. The car drove off because I assume he was tired of waiting. I was using my son's phone this morning and his girlfriend sent him a picture of a note she had gotten as I was using it. It was an anonymous hit list. And on there was "Taylor's n*gger boyfriend" which would be my son 😡

I showed my son and told her that he can't see her anymore at all. He told me that I'm overreacting and he's not gonna leave her alone when she's scared right now. I told him we need to go to the police and he told me she's been to the police but too much talking could get her into even more trouble Because she got too deep into the streets & theres that rule about snitches. I don't know what to even do anymore. We live in El Paso Texas if anyone cares.