If we’re talking about media influence / bias - then a 13 year old girl from South East London has been missing for a week (she’s black by the way) with practically no media coverage.
A mum seemingly with alcohol & mental health issues disappears and it’s all we’ve heard about for 2 weeks...
You don’t have enough details on either to make that judgement.
Brianna case seemingly more shocking that the perpetrators were a 15 year old boy and girl.