Perhaps if they were white men who were not their owners, yes.
And I am not saying that many even occurred with intent to kill, but rather punishment that unintentionally resulted in the accidental death of a slave. (Either way, little consolation to the one killed.)
The very fact they could be killed/murdered for trying to escape, or fighting back against a white owner, or if taken prisoner by the South, killed instead of kept as a prisoner of war, I am not portraying it inaccurately. To say that a plantation owner could not make an example out of a rebellious slave by executing them without fear of being prosecuted for murder is accurate.
I’m not saying that you are not in general practice correct, simply that in legal theory and occasionally in fact a white man could be executed for the murder of a slave.
Wiki: In 1811, Arthur William Hodge was the first slaveholder executed for the murder of a slave in the British West Indies.[41] However, he was not (as some have claimed) the first white person to have been executed for killing a slave.[42] Records indicate at least two earlier incidents. On November 23, 1739, in Williamsburg, Virginia, two white men (Charles Quin and David White) were hanged for the murder of another white man’s slave. On April 21, 1775, the Virginia Gazette in Fredericksburg reported that a white man (William Pitman) was hanged for the murder of his own slave.[43]
Here’s a link to the SC slave code of SC from 1740. Fines an owner 700 pounds for murder of his slave. Lot of money then. Wasn’t capital, but wasn’t legal either.
http://legal-dictionary.thefreedictionary.com/South+Carolina+Slave+Code
I’m certainly not claiming there was any equality under the law, simply that random murder was not legal, at least in theory.