This is the Wikipedia account of the prosecution of William Calley after the 1968 massacre in My Lai, during the war in Vietnam:

“Due to Article 4 of the Fourth Geneva Convention excluding allied civilians from the status of protected persons in an international armed conflict, Calley and his fellow soldiers could not be legally tried as war criminals. Calley was instead charged on September 5, 1969, with six specifications of premeditated murder under Article 118 of the Uniform Code of Military Justice (UCMJ) for the deaths of 109 South Vietnamese civilians near the village of Son My, at a hamlet called My Lai. On November 12, 1969, investigative reporters Seymour Hersh and Wayne Greenhaw broke the story and revealed that Calley had been charged with murdering 109 South Vietnamese people.”

According to Wikipedia, Calley’s trial started on November 17, 1970. It was the military prosecution’s contention that Calley, “in defiance of the rules of engagement, ordered his men to deliberately murder unarmed Vietnamese civilians, even though his men were not under enemy fire at all.” He was convicted in a military court and sentenced to life in prison. Extensive appeals followed over 3+ years, resulting in Calley being incarcerated for a period and ultimately paroled.

I wonder how this bears on the current news reports of the Navy killing two men clinging to the wreckage of a boat it had destroyed off the coast of Trinidad on the assumption the boat contained illegal drugs destined for the US.