1.   In each case the hijackers bluffed the crew using fake grenades.

2.   Police later said the device was a fake grenade.

3.   Prisoners using knives and a fake grenade took over the Aghios Stefanos prison during a mass escape attempt on Wednesday night.

4.   Prisoners using knives and a fake grenade took over the prison during a mass escape attempt on Wednesday night.

5.   A source said the item turned out to be a fake grenade intended as a joke gift.

6.   Police launched a nationwide search Thursday for four convicts who escaped a maximum security prison during a riot, using knives and a fake grenade.

7.   Riots broke out there Wednesday, when prisoners with knives and a fake grenade seized the warden and five guards.