I'm worried about my little sister... Please help. :(

My 10 year old little sister has made a new friend over the course of this year, and I'm extremely worried this new friend has a really bad influence on her.

My sister used to be really close and open with me, as her older sister, and she never does anything too bad, just the usual sibling rivalry stuff. Recently for the past few months, ever since she became 'close' with that friend, I've noticed she's become extremely secretive about her gadgets and when she's online. Everytime I look at her screen, she slams it shut and and screams- literally screams at me, to 'get lost.' I've noticed she only does this when she's using Skype, and 'other stuff.'

My parents are very strict about social media, and even I, as a soon-to-be 15 year old, am not allowed to use snap, insta, discord, etc.
She's never acted like this before, but wait- it gets worse.

She's been secretly sneaking on her tablet, at extremely late hours of the night, and although my parents caught her, she's started doing it again.
A couple of days ago, her tablet was left on the table, and it started getting notifications over and over again, while I was studying. I was going to switch it off, and I saw the notifs were from her friend.

To make an extremely long story short, she's been using that girl's phone number, to go on websites, and a lot of other things, which I'm pretty sure is illegal. As for now, I only know she's on discord and roblox but I've noticed that most of their messages together have been deleted. From what I can see, they are also extremely toxic to each other, almost every day, and frequently block each other, and be rude to each other, and it usually ends up with my sister saying extremely horrible things to the other girl, and other girl getting really sick of her and saying rude things back.

The girl often goes behind my sisters back and complains to me about my sister, and I don't even know one-tenth of what's happening behind the scenes.

I've also seen some messages they obviously forgot to delete, and it shows my sister and the girl swearing really badly, and this is really shocking to me, because my family repulses cussing, and it is not an option with us. The girl also sent a picture to my sister which she obviously forgot to delete, of her and the girl sticking their middle fingers up and sticking their tongues out at the camera. I'm horrified to even think about what other things they have been sending to each other, because most of the conversation from the past year has been deleted. They both also have multiple fake accounts on lots of websites, which who knows who they have been talking to on that.

My sister has also been telling extremely personal stuff about our family to this girl, and it's very, very personal, and this girl has no right to know that.

The thing that worries me the most, is online people. A couple of months ago, when she first bought Minecraft with me, before we joined online servers, I told her "under no circumstances, do not talk to people online". Later that day, by accident, I saw she was private messaging a guy on Minecraft, and I became very suspicious and when I dug a little deeper, I found out he was a 27 year old adult, and he was flirting with her, and she had no idea (or so she claims). After that, I wanted to found out what he was doing and chatted with him for a while, and was horrified to see that he started flirting with me, and saying extremely gross inappropriate things. I was to report him, but he left and I forgot his username. Either way, even if my sister didn't know, it shows that she has no idea about how to be safe online, and if she did know, then flirting with an adult is just disgusting, and it shows she can't be trusted online.

I haven't had access to her discord account yet, but I don't know what I should do when I do gain access. I desperately feel the need to tell my parents what's going on, but I don't want to get her into trouble, as I know the punishment will not be good. It's more than likely my dad will cut off all contact with this girl and her friends, and take her tablet and laptop away forever. Her trust in me will also likely go away forever, and as she's my sister, it breaks my heart to even think about that. I haven't told anyone, and I really don't know what to do. We are currently in a stressful situation at the moment, and I can't bear to add more stress onto my parents. Please give me advice on what to do... Thanks.

Hi, I think you need to sit down with your sister, maybe go for a walk so you are away from the house, and talk to her about all of the dangers online. Explain to her that it is very easy for someone to get hold of her contact details and find out where she lives if she isn't careful about who she talks to. Let her know that there are people out there with very bad intentions and unless shes careful she could be in danger.

Talk to her about her friend and find out whats going on with them, why they talk to each other in that way and who she is.

It sounds like your family are really strict which means that any chance your sister has to break the rules, shes probably going to. Especially at a young age, she is probably naive and doesn't fully understand the consequences.

Finally, I would tell her that you will have to tell your parents if she carries on, maybe don't mention her friend and the messages but that she is being dangerous online. They have a duty to protect her and would probably want to know. Its a hard position to be in but I understand you want to look out for her and keep her safe. If you cant speak to your parents btw maybe speak to a teacher at school.. good luck!

I've tried talking to her about online safety and other things like that so many times, but her response is, "shut up. You're not my mum." And then she goes off and does whatever it is she was doing again. Also, she doesn't know I know about all the sites she goes on, so she will pretend nothing is happening, like, "It doesn't matter, because I don't use those things anyway."
My sister's friend has many times before complained to me about my sister, and so my sister has been punished by my parents several times for acting rude to that girl, and when I try talking to her about it, she just tells me to, "shut up and get lost."
She's gotten into trouble many, many times in the past, for doing stupid things, like stealing my things, sneaking on her tablet, downloading games and stuff sh isn't supposed to, but all it does is make her try to be better at hiding things.
And I think I might have to tell my parents, but I can't at the moment, because they are currently stressed about something to do with my dad's work, and this will no doubt put more stress upon them.
For now I'm just taking screenshots of her messages and pictures for proof, because they both seem to be deleting messages straight after texting. Hopefully, I might be able to hint at my dad or mum to check her Skype, and then they will be able to see for themselves.
I'm also kind of worried that I might get into trouble for going through her messages on Skype, but then again, I found out by accident, because she forgot to turn off her notifications, so it popped up on the screen. My parents might tell me off for 'acting like a parent' and idk, it's a lose-lose situation honestly...