When you use the word 'deserve' you are assuming a MORAL CRITERIA by which to
judge the 'deservedness' of someone.  A moral criteria is like a moral law, which requires moral law-giver.
 
What you've really done is to assume that God exists... ;>)

Actually, no one really 'deserves' to be saved.  We are only saved when we trust in the Saving blood of Christ.  We are saved by grace, on the basis of God's mercy.

A murderer, then, will not 'deserve' to be saved any more than Mother Teresa does!  In fact, deservedness has NOTHING to do with salvation.  Thus the question of 'deservedness' is really a non-issue.

If anything, 'last-minute' conversions to Christianity from a previous lifesyle of extreme sin shows even more beautifully the sufficiency of Christ to save even the worse of sinners (and the latest of the 'late-comers' into the kingdom of God...).
 

Regards,
AL