Another case of murder by social media

What an appalling story, again illustrating the harm of social media:

Eight people have been killed in vigilante lynchings in Bangladesh sparked by rumours on social media of children being kidnapped and sacrificed as offerings for the construction of a bridge, police have confirmed.

The victims, which include two women, were targeted by angry mobs over the rumours, spread mostly on Facebook, that said human heads were required for the massive $3 billion project ($4.3 billion), police chief Javed Patwary said.

"We have analysed every single case of these eight killings," Mr Patwary told reporters in Dhaka.

More than 30 other people have been attacked in connection with the rumours.

Mr Patwary said police stations across the country had been ordered to crack down on rumours, and at least 25 YouTube channels, 60 Facebook pages and 10 websites have been shut down.

AFP has identified several posts still on Facebook that share the rumour, however.

Mob lynchings are common in Bangladesh, but the latest incidents are particularly brutal.

Do these countries where rumours that lead to lynchings spread like wildfire on social media try to educate the public that they cannot believe everything they read?

How hard is it for Facebook to have a local office that gets notice of a dangerous rumour and shuts down the account immediately?  Is part of the problem that you can't easily search Facebook content?  Does Facebook itself have the ability to immediately search posts across all accounts? 

Many questions I have.