What is the ruling on an inheritance mixed with industrial tools, where the heirs suspect that a portion of it was taken without right, and it is impossible to distinguish it or difficult to return it?

It is not permissible to take another's property without right. Whoever does so must repent and return the rights to their owners. If the thief dies, their heirs must seek forgiveness for them, give charity on their behalf, and return the stolen property. If they do not know the exact amount, they should return what they believe to be most likely, along with compensation for any damage and the equivalent of rent. If direct restitution causes harm, they should return it indirectly.