A killsteal is taking a mob from a group/person, that has been camping a spawn point for a long time, by getting a single shot off when you just fly in/by.
If two people are camping the same spot....even for 5 minutes...they both have the same right to the mob.
Now here is the fun thing with E&B. Players cannot Killsteals. You can in most MMO's but not in E&B.
Whoever does 51% damage (or the highest percentage if 3 or more players are all attacking) gets the credit for the kill....period. If you fail to get credit it is your own fault. Either you do not have good enough weapons, are not the right class, are not using the right tactics, or did not bring a strong enough group/player (gun) with you. In any of these situations the responsibility for the loss of the kill is on the person that did not understand the E&B design team/Westwood's design for getting credit for a kill.
Do Not Try to Accuse other players of KSing, threatening them, or their guilds with your childish inability to understand the game functionality.
Yes, this goes out to a specific person....and yes I do not apologize for bringing a bigger gun. Use your resources (guildmates, alts, better gear, guild relationships, grouping, tactics, etc) so that in the future you will get the kill. Just because you have been "camping" a spot does not mean a mob belongs to you.
I will finish by saying this: The game is pre-Alpha....the mobs have very basic AI and many skills that do not work. Learn the game, test it, generate bug reports, and have fun. Please do not devalue the work that this wonderful Dev team has spent with childish and threatening behavior.