Here is another author who seems convinced that information that the three were likely to be dead already as the search began was deliberately suppressed in order to justify a mass wave of arrests of Hamas operatives.
The author, a Christian minister based in Jerusalem, is staunchly pro-Israel and quite supportive of the Israeli government. His ministry has offices in the United States, Canada, Israel, New Zealand and the United Kingdom.
It seems apparent to this writer that due to the frightened telephone call from one of the Israeli boys, along with the ten obviously muffled gunshots, Israeli intelligence must have been aware that the boys were dead, but everyone else was living in hope. However an incensed Israeli leadership used the opportunity to gravely weaken Hamas in the West Bank by operating a dragnet, capturing every Hamas leader and operative found while searching for the boys or their bodies. (Ramon Bennett, Gaza!: The Fallout From Premeditated Barbarianism, 2014, Chapter 2, July 16, 2014.)This statement does not necessarily prove his assertion but it does show that this idea seemed perfectly plausible even to a pro-Israel writer such as him.