Our lifes could be at risk??! Help us please!!!?

I came to my best friends house 4hours ago and i was all happy and stuff but now we're both terrible. Her mother has gone to work. She doesnt know anything, the stepfather pretends to love my friend a whole lot but when shes home alone with him he beats her up. why? because my friend has refused to do as she was told. He asked my friend to undress my friend refused then he told her that he will be kind and will give her 2 options: either get beated up or d. This man is seriously sick and crazy.. my friend choose getting beaten. she had no other choice. And when i was coming around her house i didnt call her because i wanted to surprise her.. when i arrived at the door i heard screams of my friend and i rang the doorbell continuously.. i thought that maybe theres a burglar or someone. then my friend opened the door and said that she was just playing a game on who would scream the loudest with her stepdad. i didnt get surprised because they were really close but actually not. I went over to her stepdad and said hi and asked if hes fine and stuff.. then i went in my friends room and got on her laptop her msn was on remember my pword so i signed in. As soon as i signed in a offline message popped out. It was from her stepdad and the date it was sent was 5mintues ago it wrote; WE'LL HAVE ME AND YOU TIME TOMMOROW THEN.her father has a laptop too) i asked her about it and she told me everything. i asked her why she didnt tell me by then we were both crying.. she said that he would kill her if she had told a soul. then, i quickly got out of the room and shouted at him and asked him who the hell he think he was and that ill get him arrested. he slapped me and i just stood there and then i made a quick move to the homephone but he was quicker then me, he grapped the phone off my hands and told me to get in my friends room or else........ i was afraid.... i did as i was told. he is a creature, we locked the room and waited and waited for him to get out of the house but he wont. hes still in the living room .. we are too terrified to get out... and i left my mobile phone in the living room and so is my friends there...... my friend lives in an skyscr so we cant call neighbours or something.. arghhhhhh we cant do anything??? HELP. can i call the police on the computer or something.. i tried messaging my friends but none of them will believe me they wont phone the police...... bunch of fake friends. we are both 14. now what should we do>????? my friends mother is comming home 4 hours later....? will we survive until then i dont know. and i told my mum that i will be sleeping here so she wont come to pick me up.