To believe sis(12) over SD(11)?

I’d be curious to see if any other texts were sent that night off either phone. I’d also be curious to see if either one ever sneaks onto their phone at night when they’re kept on the landing.

Maybe set up family therapy? See what the crux of the jealousy between the girls.

If it is a message, then you can call the phone from a nasty message and check if it calls your sisters phone, if it does then you need to think if it was sent, or the phone borrowed the messages sent and deleted.
If your sisters phone is locked unless it was while she slept you 100% know she sent it.

Plus your SD must have some reason to be so scared...

A techy person may be able to view any deleted messages, it is possible for someone who is tech savvy

You've only got the person who was accused of sending them saying they don't particularly care about. When I was a teenager there were loads of things I said I didn't care about when I did and they were for multiple reasons.

The OP also said that her sister sounds unbothered, it's done over message there is no way of knowing. Anyone can sound unbothered over text.

It also didn't sound like SD didn't like her sister, more that they were different and had a cordial relationship.

Whatever has happened the SD is hysterical over it which either way has to be sorted.

We don't need to get into complex pyschology here.

Its your home, you set the rules about how people behave if they live in your home. Teenagers have a million problems on a daily basis. They also have little impluse control which is why consistency is important.

Keep an eye and if it escalates and there are some issues and then consider speaking to a professional (not randoms on mumsnet).

Did they definitely come from your sisters number? Did SD somehow send them to herself? If not then they had to have come from your sister, because surely if she found these random messages on her phone she knew nothing about she would have brought it up first

It really sounds like you just want to believe your sister. If you do that and she’s lying, your sd is going to feel very let down and that she has no one to help when things go wrong and your sister will think she can get away with anything. You need to get to the bottom of it without taking sides with no proof either way!

Sending someone a bunch of vitriolic messages about stuff you don't particularly care about, when the'yve been right there, and you could just have said something to them: fairly unlikely, and no upside to doing it.
Faking being sent messages to get someone you don't like in trouble: all too likely. Sounds like your SD wants your sister out of the way.

But if your sister did do it, then of course she's going to deny it. She's not going to proudly come out admitting to sneaky behaviour.

Whatever is going on, it's clear there needs to be some support put in, and sending one of them away isn't going to help either of them

This .

Regardless of the messages there must be a problem bothering whoever has sent the messages . You need to get to the bottom of what’s going on and you need your DH on board with this .

If you have a strong feeling that SD is at fault, but she is also the child who is upset, then I personally would stop investigating now. If you pick one child out as lying (even if you are 100% sure) without proof it is going to make the situation worse.

I'd spend some one-to-one time with each of the girls reinforcing how much you love them; have some chats with both of them about self esteem; and about internet safety. And then do a piece of reconciliation work with both of them focused on something like women support each other rather than specifically about this. I'd also make it very clear to both girls that nothing either of them ever does would stop them both being welcome in the house.

In response to the messages themselves I'd make a big fuss about stopping it ever happening again. I'd change the evening rule so that phones are plugged in downstairs and I'd put some sort of parental controls onto both phones (if you can) so that you can see what is sent. Plus an opening code on both phones which you know but that the other child doesn't.

Next time your sister comes to stay I'd also invite someone over to change up the dynamics a bit so that there is a bit of a buffer.

First, are you absolutely sure that the messages you reviewed on your SD's phone came from your sister's phone (or from one of her accounts - it's hard to talk about this clearly without knowing what type of messages they were)? There's no possibility that it could be a spoofed address, or an account set up to show your sister's name as a display but not actually from her phone/account? Is it possible they could have been sent by a third party - let's say, maybe, a friend of one of the girls who's irrationally jealous of the relationship? Or someone in your family trying to manipulate the situation?

If you're sure none of that is possible and one of the two girls sent the messages, I still would not take sides, at least not yet. DS has said she doesn't want to see your sister - OK, she doesn't need to right now as sis is home. But eventually sis will be back, so I would help your SD prepare for that. If she genuinely chooses to go to her GP's to avoid your sis, that's one thing - but why on earth would you say she HAS to go to the GPs?

You have a problem to sort out regardless of who sent them

first of this is your SD home you cannot ship her off to her grandparents

second not getting that and the impact your sister has coming to visit on her in her house may well be part of the problem

the thing is your SD should be the priority it is her who is the child not the sibling. Talk to her and work out what it is that is bothering her - because it is clear something is regardless of who sent the messages

You do seem to be taking one side more than the other with very little concrete reason as to why.

But regardless of who did it, all behaviour is communication. I'm not saying that there shouldn't be consequences, but this hasn't come from a place of security and happiness. There's a bigger issue here that needs to be explored and dealt with compassionately.

The phones need to be in a lock box overnight

My sons phone opens with his fingerprint I can unlock it with a code though so the only person it stops is his brother

It does sound like jealous behaviour fron SD is quite likely though

I wouldn't even try doing cross-questioning and looking in the eyes. I would seat them down and tell that this is not to be repeated, and phones will not go to bedrooms at night.

If SD is lying she clearly has big issues with your sister. Which need resolving regardless.

If Sister is lying you’re asking sd to have someone bullying her in her home.

tricky.

This!
The worst thing OP could do would be to ship her off.
Maybe the lie needs to be outed by whomever told it and some bonding and security needs to be put in place.
It sounds like both girls have been somewhat shipped off to OP’s house for various reasons.

Had SD not been on her phone the whole day until your sister went home?

I don't think you should frame it as picking one over the other. Sit them both down calmly and say that you need to know the truth. Tell them that you won't get angry if they're both honest and then sort out whatever it is that causing one of them to act out

Agree to adding passwords (that you know) to the phones, and I would add that phones are brought downstairs (not left in the landing where they are easily accessible) overnight.

Highly unlikely, why would she do that?

@Dramatic this is true actually you have a good point. I suppose pre teens don’t think this rationally. Back in my day it was reversed charges and knock-a-door 🤣🤷🏼‍♀️

I would find it hard to believe that SD crept out in the middle of the night I text herself off of sisters phone and then deleted the evidence.

It is much more likely that sister texted SD and then deleted them herself (or will do).