Killing a soul is not allowed whether Muslim or Non Muslim.

Killing a soul, Muslim or non Muslim.

Allah says:

“Because of that, We ordained for the Children of Israel that if anyone killed a person not in retaliation of murder, or (and) to spread mischief in the land – it would be as if he killed all mankind, and if anyone saved a life, it would be as if he saved the life of all mankind” [al Maaidah verse 32]

al Hasan (Basree) was asked regarding the verse

أهي لنا يا أبـا سعيد كما كانت لبنـي إسرائيـل؟ فقال: إي والذي لا إله غيره، كما كانت لبنـي إسرائيـل وما جعل دماء بنـي إسرائيـل أكرم علـى الله من دمائنا.

Is this verse applicable on us like it was on Bani Isra`eel? He said: yes By the one who is only Ilah, the blood of Bani Isra`eel is not better than us in the sight of Allah. [Tafsir at-Tabri under al Maaidah verse 32]

I.e. when it is not allowed to kill the people from Bani Isra`eel then how can it be allowed to kill the Muslims?

Ibn Kathir said:

أي: من قتل نفساً بغير سبب؛ من قصاص أو فساد في الأرض، واستحل قتلها بلا سبب ولا جناية، فكأنما قتل الناس جميعاً؛ لأنه لا فرق عنده بين نفس ونفس، ومن أحياها، أي: حرم قتلها، واعتقد ذلك، فقد سلم الناس كلهم منه بهذا الاعتبار،

The Ayah states, whoever kills a soul without justification — such as in retaliation for murder or for causing mischief on earth — will be as if he has killed all mankind, because there is no difference between one life and another. [end quote]

Ibn Taymiyah said:

وذلك أن قتل الجن بغير حق لا يجوز كما لا يجوز قتل الإنس بلا حق والظلم محرم في كل حال ؟ فلا يحل لأحد أن يظلم أحدا ولو كان كافرا بل قال تعالى : { ولا يجرمنكم شنآن قوم على ألا تعدلوا اعدلوا هو أقرب للتقوى }

Killing the jinns unjustly is not allowed like it is not allowed to kill a man (kafir or Muslim) unjustly. And Dhulm (unfairness/oppressing) is not allowed in any situation, it is not allowed for anyone to do dhulm on other even if he is a kafir, Rather Allah says: “and do not let the hatred of a people prevent you from being just. Be just; that is nearer to righteousness.” [Fatawa Ibn Tamiyah 19/46]

Verdicts of Umar ibn al Khattab against a mob who killed a boy.

Ibn ‘Umar said:

A boy was assassinated. ‘Umar said, “If all the people of San’a took part in the assassination I would kill them all.”

Al-Mughira bin Hakim said that his father said, “Four persons killed a boy, and ‘Umar said (as above).”

Sahih al-Bukhari 6896

Scholars did not differentiate Muslim and non Muslim in this regard.