So, to our credit, we invented religion"

No, to mans credit he has invented millions of religions each proclaiming that it is the real truth.

All of us have sinned:

NIV Romans 3

22. This righteousness from God comes through faith in Jesus Christ to all who believe. There is no difference,
23. for all have sinned and fall short of the glory of God,
24. and are justified freely by his grace through the redemption that came by Christ Jesus.

NIV Romans 6:23
For the wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord.

But...

NIV Matthew 1:21
   She will give birth to a son, and you are to give him the name Jesus, because he will save his people from their sins."

NIV John 1:29
   The next day John saw Jesus coming toward him and said, "Look, the Lamb of God, who takes away the sin of the world!

NIV Romans 8:1-2
1. Therefore, there is now no condemnation for those who are in Christ Jesus,
2. because through Christ Jesus the law of the Spirit of life set me free from the law of sin and death.

Do the ex-Khmer murderers, if their faith is sincere, go to Heaven?
According to the Book; Yes.

NIV Mark 3:28
   I tell you the truth, all the sins and blasphemies of men will be forgiven them.   (all; not SOME)
NIV Matthew 12:31-32
31. And so I tell you, every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven.
32. Anyone who speaks a word against the Son of Man will be forgiven, but anyone who speaks against the Holy Spirit will not be forgiven, either in this age or in the age to come.
NIV Matthew 6:14-15
14. For if you forgive men when they sin against you, your heavenly Father will also forgive you.
15. But if you do not forgive men their sins, your Father will not forgive your sins.   (But beware...)

NIV Matthew 18:21-22
21. Then Peter came to Jesus and asked, "Lord, how many times shall I forgive my brother when he sins against me? Up to seven times?"
22. Jesus answered, "I tell you, not seven times, but seventy-seven times.
NIV Romans 4:7-8
7. "Blessed are they whose transgressions are forgiven, whose sins are covered.
8.   Blessed is the man whose sin the Lord will never count against him."

Given that most of ther victims were not Christian, do they go to Hell forever?
Depends...... (also, according to the book.)

NIV John 14:6
Jesus answered, "I am the way and the truth and the life. No one comes to the Father except through me.
NIV John 15:22
   If I had not come and spoken to them, they would not be guilty of sin. Now, however, they have no excuse for their sin.

NIV Romans 2:12-16
12. All who sin apart from the law will also perish apart from the law, and all who sin under the law will be judged by the law.
13. For it is not those who hear the law who are righteous in God's sight, but it is those who obey the law who will be declared righteous.
14. (Indeed, when Gentiles, who do not have the law, do by nature things required by the law, they are a law for themselves, even though they do not have the law,
15. since they show that the requirements of the law are written on their hearts, their consciences also bearing witness, and their thoughts now accusing, now even defending them.)
16. This will take place on the day when God will judge men's secrets through Jesus Christ, as my gospel declares.

So, are you saying that since there are a lot of false one's; then NONE can be real??

WOW!

That was a big mispost!!!

No, to mans credit he has invented millions of religions each proclaiming that it is the real truth.

So, are you saying that since there are a lot of false one's; then NONE can be real??

"No, to mans credit he has invented millions of religions each proclaiming that it is the real truth."

Well, either all of these religions are invented and thus nonsense, or one of them is revealed from God and thus true. If the latter, the "true" one may also incorporate "truths" from the other religions.

As a Christian I believe that Christianity is the revealed truth from God and Atheism was invented by man to escape responsibility to God.

In essence, Atheism is the opiate of the asses...so to speak.

Scientists often disagree. Why can't religious people?