In Exodus 2 Moses does kill an Egyptian but that is in retaliation to how the Egyptian had treated one of his brethren:
2:11 And it came to pass in those days, when Moses was grown, that he went out unto his brethren, and looked on their burdens: and he spied an Egyptian smiting an Hebrew, one of his brethren.
2:12 And he looked this way and that way, and when he saw that there was no man, he slew the Egyptian, and hid him in the sand.
2:13 And when he went out the second day, behold, two men of the Hebrews strove together: and he said to him that did the wrong, Wherefore smitest thou thy fellow?
2:14 And he said, Who made thee a prince and a judge over us? intendest thou to kill me, as thou killedst the Egyptian? And Moses feared, and said, Surely this thing is known.
But Moses did immediately realise his actions were wrong so I wouldn't say he was a murderer, but he did commit the act. The Bible does not call him as such neither does it condemn him. The law of the land does say it is wrong but God still placed His trust in Moses. He gave Moses the ability to lead the Jews and performed holy miracles because God saw Moses as HIS prophet and leader of The Chosen People. I feeling is that calling Moses a murderer is a moral judgement, one that can be made by they themselves who have no sin and can be called upon by the Most High to perform His works. It would be interesting to know how the I them feel also.