Proverbs 28:17 Really? Yes, really.

¹⁷ A man that doeth violence to the blood of any person shall flee to the pit; let no man stay him.

Anyone tormented by the guilt of murder
    will seek refuge in the grave;
    let no one hold them back.

The history of how murder was treated in the Bible is an interesting study. In Genesis chapter nine, as Noah and his family leave the ark, God gives instructions on how to handle a man who sheds the blood of another. 
In Numbers 35:33, it is stated that the shed blood of an innocent person actually pollutes the land:

So ye shall not pollute the land wherein ye are: for blood it defiles the land: and the land cannot be cleansed of the blood that is shed therein, but by the blood of him that shed it. 

Exodus 20:13 tells us "Thou shalt not kill" and then in Matthew, Jesus tells us:

Matthew 19:17b ……but if thou wilt enter into life, keep the commandments. 18 He saith unto him, Which? Jesus said, Thou shalt do no murder, Thou shalt not commit adultery, Thou shalt not steal, Thou shalt not bear false witness...

Solomon surely must have been thinking of the Psalms of his father, which say:

Psalm 30:3 O LORD, thou hast brought up my soul from the grave: thou hast kept me alive, that I should not go down to the pit.

Psalm 55:23 But thou, O God, shalt bring them down into the pit of destruction: bloody and deceitful men shall not live out half their days; but I will trust in thee.

So, then, the pit is another word for hell -- the place prepared for Lucifer and his angels. Here's what Isaiah had to say:

Isaiah 14:12 How art thou fallen from heaven, O Lucifer, son of the morning! how art thou cut down to the ground, which didst weaken the nations! 13 For thou hast said in thine heart, I will ascend into heaven, I will exalt my throne above the stars of God: I will sit also upon the mount of the congregation, in the sides of the north: 14 I will ascend above the heights of the clouds; I will be like the most High. 15 Yet thou shalt be brought down to hell, to the sides of the pit.

I believe what Solomon is saying here is that the unrepentant murderer should be allowed to flee to his own destruction, to the pit. That, however, is under the Law of Moses. The assumption here is that he is unrepentant and flees without accepting the free gift of forgiveness offered by Christ.
What should our thinking be now?
Well, we are not under the Law any longer. And under the grace of our Lord Jesus, even a murderer can obtain forgiveness if he calls on the name of the Lord. Every murderer in every prison in the land should have the opportunity to hear of Christ's mercy and forgiveness.
As much as it may rattle us, and we may say, "Really?" Christ can save that murderer. It might not be our way; it might not seem "right" to us . . . but it is definitely God's way to forgive, if in sincerity and remorse the person asks for forgiveness. (After all, He forgave us, right?!)
Let's look back into the book of Isaiah, in the 55th chapter:
⁶ Seek the Lord while he may be found;
    call on him while he is near.
⁷ Let the wicked forsake their ways
    and the unrighteous their thoughts.
Let them turn to the Lord, and he will have mercy on them,
    and to our God, for he will freely pardon.

Yes, really!