Reports of warnings of this horrific attack are said to have come from twitter account @owys663, and in a later tweet from this account he states "We have more...."
I can only imagine the satanic mind set that drives someone to target the most innocent and defenceless members of our planet, for now the problem will be stopping them and preventing more carnage.
The hard part will be finding a punishment suitable for this kind of action, death would be too easy for them.
Thoughts and prayers are with all of the people affected.