The Netanyahu government lied about the three teens they knew were murdered by a different clan and used this as an excuse to go on a violent rampage before Hamas decided to fight back with its first rocket.
http://www.alternet.org/world/noam-chomsky-nightmare-gaza?page=0%2C1
http://mondoweiss.net/2014/07/killed-turning-onslaught.html
The Netanyahu government repeated this tactic a second time and accused Hamas of breaking the ceasefire because they claimed Hamas captured an Israeli soldier, who again turned out to have already been dead. This resulted in massive destruction and death of countless civilians.
http://www.latimes.com/world/middleeast/la-fg-israel-gaza-hamas-missing-soldier-20140802-story.html