'Knife-wielding attackers kill 29, injure 130 at train station':
http://www.cnn.com/2014/03/01/world/asia/china-railway-attack/index.html
.
'Japan knife attack: At least 19 dead:'
http://www.cnn.com/2016/07/25/world/japan-knife-attack-deaths/index.html
.
Consider yourself "known."