If this is true, why would they release the information about how they did it?
Yes there is some psychological warfare effect that will make hamas people feel scared for a short amount of time, but it will also make them change their security procedures to help prevent this method from working in the future. Their forensics were going to determine that it was a bomb, but they wouldn’t have been able to tell that the bomb was planted so far ahead of time.
I’m not convinced this story is true. I’m not saying it’s false, but i am saying they had no incentive to tell the truth, and in fact they have incentive to lie so that hamas puts work into securing against the wrong method.