This comment makes no sense. It's not a trick question. If you're asking if something is a sin, you have to be look at it from a theist's/religious person's perspective and play, pun fully intended, Devil's Advocate. I'm an atheist and I can answer this easily.
The answer is yes. Murder is a sin because it's taking a life, heavy on the word taking. Because man is not the original giver of life, it's the equivalent of stealing from God, as all life come from and through him and his son. That includes your life. Sure, it's your life, but it ultimately came from and is through God, so you are not permitted to take it, or any life, unless it's something like self defense. This is why God can commit as many murders as he has and still be holy.
There is where you never understand how life and death work and how God control it.
In Islam(I dont know how other religions works on this matter) God already decide where the person will die and how they will die even before they were still a concept or sperm.
Something to share with you about human and path to life in Islam
"To find out where the creatures die, Allah has created Angels Arham will be instructed to enter the sperm in the mother's womb with the dust of the earth and will know where he was going to die and that is where later he is doomed to die.".
I know you're an atheist and never believe in this superstitious thingy but here if you want to accused Islamic God(Allah) as murderer for example, you're wrong because it already been decided from the beginning even before the human is created oh how he will die later in his/her life. How they die already been decided (suicide, old age, younger age, accident, being stab, being bomb, being shoot etc) and also only God know how to judge them, Its not
sign of murder right?
If you logically think that what still a murder act from God, why God still need to created the human in the first place?
God have right to take a life of human bcus it was God own property not you or me and yet still can be accuse as murderer by you but our God already
decided it. You see some death is gruesome or cruel but that's how they will die according to God and not to forget there is where the place the
dust of earth is taken by
Angels Arham.