Do you feel that the man who shot and killed those little girls the other day in Pennsylvania has any possibility of spending eternity with the Lord Jesus Christ? He did say that he wanted them to pray for Him at one point in his rampage. Please be specific here if you can?
While I heard of the events and read accounts of it in the paper, you are asking about something I have ability to judge. I wasn't there. I have not spoken to witnesses who were there. And most importantly, I can't see into the mind of this man to say what his motivation was in regards to this horrible event.
Let's stick to what we do know. Murder is wrong, but God particularly hates those who cause the death of innocent people. "Keep yourself far from a false matter; do not kill the innocent and righteous. For I will not justify the wicked" (Exodus 23:7). "These six things the LORD hates, yes, seven are an abomination to Him: a proud look, a lying tongue, hands that shed innocent blood, ..." (Proverbs 6:16-17).
Asking others to pray for him doesn't mean a person is forgiven or will receive what he asked. People do lie -- to themselves and to others. "You lust and do not have. You murder and covet and cannot obtain. You fight and war. Yet you do not have because you do not ask. You ask and do not receive, because you ask amiss, that you may spend it on your pleasures" (James 4:2-3). Let us assume that what you stated was true: that this man ask for prayers in the middle of his rampage. This means that he continued to kill despite what he said. His actions are not those of a repentant man (II Corinthians 7:9-11). Paul stated that people need to be taught "that they should repent, turn to God, and do works befitting repentance" (Acts 26:20). I haven't read anything that indicates this happened with this man. Jesus stated, "I tell you, no; but unless you repent you will all likewise perish" (Luke 13:3). Perhaps he was sorry that he was causing harm, but he wasn't sorry enough to change his course of action.
Job asked questions that we should all consider: "For what is the hope of the godless when he is cut off, when God requires his life? Will God hear his cry when distress comes upon him? Will he take delight in the Almighty? Will he call on God at all times?" (Job 27:8-10). Job then contends that we all know the answer: "I will instruct you in the power of God; what is with the Almighty I will not conceal. Behold, all of you have seen it; why then do you act foolishly? This is the portion of a wicked man from God, and the inheritance which tyrants receive from the Almighty. Though his sons are many, they are destined for the sword; and his descendants will not be satisfied with bread. His survivors will be buried because of the plague, and their widows will not be able to weep" (Job 27:11-15).
Elihu stated much the same, "There they cry out, but He does not answer, because of the pride of evil men. Surely God will not listen to empty talk, nor will the Almighty regard it" (Job 35:12-13).
God stated, "Because I have called and you refused, I have stretched out my hand and no one regarded, because you disdained all my counsel, and would have none of my rebuke, I also will laugh at your calamity; I will mock when your terror comes, when your terror comes like a storm, and your destruction comes like a whirlwind, when distress and anguish come upon you. Then they will call on me, but I will not answer; they will seek me diligently, but they will not find me. Because they hated knowledge and did not choose the fear of the LORD, they would have none of my counsel and despised my every rebuke. Therefore they shall eat the fruit of their own way, and be filled to the full with their own fancies. For the turning away of the simple will slay them, and the complacency of fools will destroy them" (Proverbs 1:24-31).
So, yes, wicked people will suddenly face terror brought on by their own sins. In their distress they may cry out to the Lord, but because they had refused God, He will refuse to listen to them. The truth is such "conversions" are not real; there is no turning toward God, but a rejection of the consequences of their own actions.