The first murder was indeed a religious one and it took place in the Garden.
Two humans created in the Image of God died that day, when they believed the religion of Theology.
God spoke directly to Adam & Eve - "And the LORD God commanded him, “You may eat freely from every tree of the garden, but you must not eat from the tree of the knowledge of good and evil; for in the day that you eat of it, you will surely die." Genesis 2:16
No need to question God for HE walked with them in the Garden = All is GOOD.
Until the day that Sin entered in the Garden. - Ezekiel 28:13
Thou hast been in Eden the garden of God; every precious stone was thy covering, the sardius, topaz, and the diamond, the beryl, the onyx, and the jasper, the sapphire, the emerald, and the carbuncle, and gold: the workmanship of thy tabrets and of thy pipes was prepared in thee in the day that thou wast created.
Thou art the anointed cherub that covereth; and I have set thee so: thou wast upon the holy mountain of God; thou hast walked up and down in the midst of the stones of fire.
Thou wast perfect in thy ways from the day that thou wast created, till iniquity was found in thee.
Then came Theology: Genesis 3:1-5
Now the serpent was more subtil than any beast of the field which the LORD God had made.
And he said unto the woman, Yea, hath God said, Ye shall not eat of every tree of the garden?
And the woman said unto the serpent, We may eat of the fruit of the trees of the garden:
But of the fruit of the tree which is in the midst of the garden, God hath said, Ye shall not eat of it, neither shall ye touch it, lest ye die. And the serpent said unto the woman, Ye shall not surely die: For God doth know that in the day ye eat thereof, then your eyes shall be opened, and ye shall be as gods, knowing good and evil.
The FIRST place/time the ? shows up in Scripture is that which came out of the mouth of the Serpent.
This Question MARK (HELLO) is directed and attached to to God's Word - with a ? and a Twist = Redirection away from the Command.
If you look up a picture of Budha/serpent it will show a Serpent(s) coming up from behind him and rising and hovering above him.
This is the Source of Knowledge to Budha and to the World under Sin.
Adam and Eve were murdered that day because they believed a lie that directly was the cause of their death.
We will see that the next religious murder comes from a brother against a Brother = Works murders Grace = Cain kills Abel.
IMPORTANT: If you think this is Off Base then you need to Read this: Revelation 2:13
“And to the angel of the church in Pergamos write,b‘These things says He who has the sharp two-edged sword:
“I know your works, and where you dwell, where Satan’s throne is.
Pergamos, the Elite University City of Knowledge of that day and time.
Would you not say that, once again, Satan's makes his home and throne amongst the Universities of today.