Islam has a clear rule that a Muslim is not to be killed for murder of a non-Muslim
Sahih Bukhari
Volume 4, Book 52, Number 283:
'Narrated Abu Juhaifa:
I asked Ali, “Do you have the knowledge of any Divine Inspiration besides what is in Allah’s Book?” ‘Ali replied, “No, by Him Who splits the grain of corn and creates the soul. I don’t think we have such knowledge, but we have the ability of understanding which Allah may endow a person with, so that he may understand the Qur’an, and we have what is written in this paper as well.” I asked, “What is written in this paper?” He replied, “(The regulations of) blood-money, the freeing of captives, and the judgment that no Muslim should be killed for killing an infidel.”’
Sunan Abu Dawud
Book 39, Number 4515:
'Narrated Ali ibn AbuTalib:
Qays ibn Abbad and Ashtar went to Ali and said to him: Did the Apostle of Allah (peace_be_upon_him) give you any instruction about anything for which he did not give any instruction to the people in general?
He said: No, except what is contained in this document of mine. Musaddad said: He then took out a document. Ahmad said: A document from the sheath of his sword.
It contained: The lives of all Muslims are equal; they are one hand against others; the lowliest of them can guarantee their protection. Beware, a Muslim must not be killed for an infidel, nor must one who has been given a covenant be killed while his covenant holds. If anyone introduces an innovation, he will be responsible for it. If anyone introduces an innovation or gives shelter to a man who introduces an innovation (in religion), he is cursed by Allah, by His angels, and by all the people.
Musaddad said: Ibn AbuUrubah’s version has: He took out a document.’
Is the life of a Muslim more precious than the life of a non-Muslim?