Does the LDS Church teach that murder is unforgivable?

Doctrine and Covenants 42:18 appears to teach that anyone who kills cannot ever be forgiven. Does "killing" refer only to murder or to any killing, be it in self defense or as part of a way? > And now, behold, I speak unto the church. Thou shalt not kill; and he that kills shall not have forgiveness in this world, nor in the world to come. D&C 42:18 Does the LDS Church hold to this position today? If so, how is God's forgiveness of David reconciled with that as well as the people mentioned in the book of Alma? > Nathan said to David, “You are the man... You have struck down Uriah the Hittite with the sword and have taken his wife to be your wife and have killed him with the sword of the Ammonites... David said to Nathan, “I have sinned against the LORD.” And Nathan said to David, “**The LORD also has put away your sin**; you shall not die. 2 Samuel 12 (portions) ESV > > And I also thank my God, yea, my great God, that he hath granted unto us that we might repent of these things, and also that **he hath forgiven us of those our many sins and murders which we have committed**, and taken away the guilt from our hearts, through the merits of his Son. Alma 24:10