Stuff stealing. ..

[BertmacklinFBI]

11 year old dd2 is constantly taking things that aren't hers. Mine and elder dd13 in particular. Food, clothes, make up, money. If it's not nailed down she WILL take it.
She then lies about it even though we have proof. Ie actually caught her, seen her etc.
Dd13 has just text me to say she's taken one of her new birthday books and when confronted said she's left it at school.

Honestly I don't know how to get her to stop!
It's all the time.

assuming no psychiatric issues; removal of all privileges and non-essentials. Take her prized possessions and sell. Explain calmly and clearly that this will continue until she can be trusted.

if they've got separate rooms, a lock for the older one.