菲律賓事件!

但有沒有相關條例講明可以在那些時機狙擊槍手呢?

The answer above is already well enough, but just let me elaborate a bit more.

In most Law Enforcement Agency(LEA) across the world, sniper can be used only as a last resort to dissolve the crisis.

In fact, most LEA would forbit the use of Tactical Sniper should be use when all else fail. And basically there are 3 factors leads to the use of tactical sniper/marksman

1.) When the HT(Hostage Taker) had killed or likely to kill any hostage
2.) When the HT loses contact with the authority (Audio/Visual)
3.) WHen the HT enter a state of mental unstability.

Not all Police Agency follow these, some have strighter guideline, some have less, for example, UK CO19/SAS only shoot the HT when they had killed hostage and had confirmation of the attack.

FBI HRT on the other hand, would advice the use of sniper sometime even when the hostage is not harmed or not intented to be harmed (althought only follow stright guideline)

from the point of law, police sniper is still law enforcement officer, not a judge, they have no right to sentence any one to death. Not even the HT. Only in protect themselve or protecting other, they are allow to fire

in that incident when mendoza release the hostage, he does not post any threat to the police or the hostage (Actually he is doing the opposit thing) So, olice sniper have reason NOT to open fire. This is what most people misunderstood when they apporach this incident. Yeah, sniper had a chance, but no reason to fire then.

菲律賓特警一開始時係曾經有好幾個機會槍手在前門出現,但當時仍在談判階段，再者槍手在當時未有危害人質嘅行動，狙擊手在如此情況及未有上級命令，係幾好時機都唔會 send the bullet！

菲驚之所以唔識把握狙擊的良好時機，
因為『蠢人冇藥醫、人懶及豬肥 』！

其實佢攞住支M16然後又脅持人質,已經可以用狙擊槍打爆佢個頭。

當日槍手有好多次暴露出弱點,為何狙擊手不能遠距離槍擊他?
基本上他協持十多人命,殺他都無須解釋理由,又可以射他手、腳部位,
使他失去協持人質能力便可,麻醉槍亦可使用....

或者用陰謀論講,佢地唔係想要錢,係想搞出人命,
亦可以解釋到,呢次唔係意外,係一場show!!!

因為槍手當時沒犯明顯的死罪(例:殺人)
如果那時候直接殺死槍手可能會招來社會間不滿的言論

馬尼拉警方應該把握當時的機會
衝前制服槍手
而不是狙擊手殺死槍手