They set off bombs, then shot everyone as they left. Then they shot at the first responders.
I've been thinking & saying this for years.... It was only a matter of time before terrorists got smart and start using military tactics to these attacks. Why send in a single bomber to kill thirty people when you can put bomb in place, kill thirty, and then kill hundreds more as they flee.
Here in the US we are huge targets. Wait until they attack an oil refinery and set it off. It will kill thousands.
Egypt Mosque Attack Kills 235, Injures 109: State Media | Time