A ride for the murderer. To turn him in?

I don't have his name, but I have enough identifying details that if the IDF wanted to, it would take a few minutes to locate him.
I'm sure of the story and he gave the impression that it was more than a one-time event but a kind of routine for him and a simple understanding of what he thought he needed to do, although he didn't say that explicitly.
He wasn't excited, he wasn't upset, he was just flowing.
And he didn't understand why it was even interesting.

By the way, at the time of the incident, I felt sorry for him regardless of his actions.
He is a poor soldier and grew up in a poor home. The type of weapon he is entrusted with is very heavy and when it lasts for a long time, it hurts various parts of the body. The army doesn't provide a belt that costs several hundred shekels. I gave it to him and he promised that with the money he would hurry up and buy the belt for himself.

I asked if I had to report it?
Or maybe his friends would stop him from continuing (I know where he belongs, I don't think it will happen..) and maybe he would make a confession of himself?

I wrote my opinion. Murderers should be dealt with. I'm of course not convinced that he wasn't just bragging (in itself a serious matter), but this should be checked and investigated.

Miki, with all due respect to the blog here, it is impossible to rule on the laws of souls from the sleeve or from the stomach, just as you would not let Oren answer this, a tedious bot (write him at most like Rabbi Chaim Kanievsky, who used to write that when you are (in Lod), you will enter Eli). Just like that, Miki, for sport. Did you know that according to the Maimonides, killing a Gentile is forbidden because you shall not destroy?? (and not because you shall not murder) and you pull out a ruling right out of your sleeve to put him in prison for 25 years and his blood and the blood of his offspring depend on Miki's rulings?

There is something that is more ridiculous to me than idle talk, and that is firm idle talk. And even more so firm idle talk accompanied by righteous reprimands.
And even though these idle talk are not worthy of a response, I will nevertheless write a few comments for the majority of your affection in my opinion:
1. Indeed, he is not liable to death for it (Heb. 11:1). But can you enlighten me as to where you learned the matter of not destroying in the Rambam? I did not find it in either Heb. 7:7 or Heb. 10:11, and we certainly did not find that killing a Gentile is a sin only because of this. But apparently the matter is not empty except from me.
2. In Heb. 11:3, the Rambam obligates the one who kills a Gentile by mistake to exile. I have not heard that exile is obligated for not destroying. It is possible that I omitted Minai that even someone who throws away a tomato that is left over after eating will be subject to exile, and that's simple.
3. See Hal' Rotseh P"2:3 and Hal Melchim P"9:4 on killing a Gentile and in the commentaries there.
4. Of course, all of this is just to magnify the Torah and glorify it, but it is not relevant to the discussion, since we are not dealing here with the laws of the Torah but with the laws of the state and morality. And by these laws and by those, he is a complete murderer and deserves to be scummed by sitting in prison and never seeing the light of day for the rest of his days (and not just 25 years).
5. It is puzzling to me that a great scholar like you says that one cannot pass judgment on this from the sleeve, but you write your words completely from the sleeve. And it is no less puzzling to me that you spare the seed of the aforementioned murderer but you have no problem with those he murdered and their seed. You are a great stricter in prison laws and a great lenient in the law of murder. Bless you.
6. The Holy One rebukes Israel for saying, "Singing about the sea, when the work of his hands is drowning in it." Apparently they were afraid lest it be destroyed, and it is a wonder that they did not put their heart into it. And the devil.

There is more to be said about these words of wisdom, and I have come only to comment.
My woe, the rebuke (he too would have withdrawn and wept).