well, i dont have experiences related to this but so far as i can see: you make things the harder way.
why dont you call the police and take each of the three to the lie detector test immediately you know someone have lied?

you follow the general routine almost perfectly only to get a quite messy result. yeah, there are options out there for you to take when dealing with this kind of stuff, but you have to reason the situation well and make the very best choice out there instead of going through all that is suggested.

well, its not your fault. moms are likely to panic when her children is not fine.