My parents have gone away on a cruise for 3 weeks. Left last Thursday and asked me to housesit and to look after DSis who was 18 2 weeks ago.
My parents said she could have a party last Friday night (yeah, cheers for that one 
). I wasnt told anything about it until last Wednesday evening. Mum said it would be max 10 friends and she agreed they could drink but the rules were no spirits and no smoking indoors (both me and DSis smoke but we know to smoke outside or in the garage)
Anyway DSis and me went to the supermarket last Thursday and brought some beer and cider and alcopops. Set some extra ground rules: anyone carrying alcohol on the way into the party would be turned away, I would be checking on them all every so often and if anything iffy was happening I would be pulling the plug straight away. And I set a curfew to have everyone apart from her 2 best friends to be out by 1am.
It is worth pointing out here that DSis has friends varying in age from about 14-25. She does some volunteering, has a part time job and goes to college so has friends from those places.
DSis and everyone turned up at the house about 7.30pm. Everything seemed fine. Nobody turned up with extra alcohol (to my knowledge at the time). There was an extra 4 people but I let it go.
About 8.30 and I was cooking some pizzas in the kitchen. 2 girls came in and
asked where they needed to go to smoke and I pointed them in the right direction. Didnt pay much attention to them tbh as the beeper went on the oven and I was trying to Skype my DP at the time.
Took the pizzas in and all was OK until about 10pm when DSis came in and said one of her friends had been sick behind the sofa and was drunk. Cleaned her up and took her upstairs and put her to bed in Dsis bed where shefell asleep. I asked Dsis if she knew her Mums number- her phone had a passcode on it so I couldnt get in to to get the number. DSis just ensured me that the girl was just a bit of a lightweight and had got carried away.
I told her it was time to wrap things up. Went into the lounge to find they had smuggled bottles of vodka and tequila in and had been doing shots (I had gone into the louge to get the girl but they had hidden the evidence behind the other sofa) and that they had been smoking out of the window of the lounge. Kicked everyone out and told them that if they came back id be calling the police to escort them all home to their parents which funnily enough got rid of them all. DSis told ne later they had hidden the bottles under the hedge and when the two girls went out to smoke they brought it in
I was furious with DSis and told her that aside from college, work and her volunteering she wouldnt be lesving the house until she was my parents reaponsibilty again and that id be taking her and collecting her. Ive managed to confiscate her bank card and I know she doesnt have any cash so shd cant get anywhere without me anyway.
Let the girl stay the night who I then dropped off the next day. She insisted I dropped her at the corner of the street, but I drove her to the front door. She let herself in and there were no cars about so her parents musnt of been in.
Anyway all was OK until today when I got a phone call from the girls mother. It turns out she is only 14, had never had alcohol before and had been told by their DD she was just going to a sleepover at a different friends house.
Theyve said they are ringing the police for supplying alcohol to a minor and that they will be making my employer aware. I explained the situation (that I was DSis, Mum gave permission for the party and the alcohol and gave us the money to pay for it.) but they didnt care. The girl was incredibly hungover and apparantly told her parents everything
Im shitting myself. Im furious. If i get a criminal record, a warning even, I will more than likely loose my job. DSis is remorseful but it isnt good enough. Ive sent her to stay with my grandparents for the remainder of my parents trip who are uncontactable as they are on a cruise and obviously cant get phone signal in the middle of the Atlantic. This will be the case until Sunday.