I am not familiar with Israeli law, but in the United States the prosecution must only establish the defendant intended to commit great bodily harm to the victim knowing the act could cause death. Only in 'attempted murder' does the prosecution have to establish the specific intent to kill someone. It's clear here the defendants intended to stab the victim. It's also pretty clear stabbing someone in the head can cause death. Here we could easily charge him with murder. The accomplices could also be charged with it, but prosecutorial discretion is sometimes used if they were not as involved as the main defendant in the actual stabbing/attack. Manslaughter is actually very similar to murder in that it still requires this basic pseudo intent principal of knowingly causing someone great bodily harm that could likely result in death. The only different w/ VOLUNTARY manslaughter and murder is the existence of an aggravating factor. For isntance, an unreasonable belief that your life is in danger. If an unarmed person comes up to you on the street and angrily says "give me your money!" and you pull out a gun and blow his brains out this would probably constitute manslaughter. Even if you thought your life was in danger. In this instance you clearly intended to kill this person, but the surrounding circumstances were different. So, in sum, you're a moron.
U.S., allies stage 20 strikes against Islamic State in Iraq (Reuters)