After initially ridiculing as fake a video that appears to show army soldiers massacring civilians, the government of the Democratic Republic of Congo in Kinshasa abruptly changed course and announced Wednesday that it was opening an investigation into the matter and that several soldiers had been arrested. The disturbing video surfaced last week showing what appeared to be Congolese government soldiers walking down a country road and then shooting at least a dozen people standing in front of them. Human rights activists said the video was taken this month during a counterinsurgency operation in the central Kasai province and that it was evidence of war crimes. News of the death, which coincided with this week’s announcement that U.S.