do i need to become a murderer?

i've been in a relationship for a month now and my partner's ex is stalking her and stalking her everywhere. last night he threatened to kill me and put his hands around my neck. i've gone to the police to try and get them to take charge but they give me an emergency number to call and nothing happens. today this guy showed up at the salon where my girlfriend is getting her nails done and they had to call the police. when i got there to pick her up i was ready to kill him. i can't stand this situation anymore my girlfriend is in constant fear we can't live a normal life. she doesn't feel safe going anywhere alone. and i'm starting to feel so arrogant in this situation because i know that's what the law is for but if we don't get a restraining order by this monday.... i'm going to hunt this guy down and when i catch him he's going to know that he should always be afraid of the demons we can become for love.