When Palestinians are killed, the killers are not known, according to the Times

Look at this paragraph: "Since the uprising began in October, Palestinians have killed 18 Israelis and an American citizen. More than 115 Palestinians have been killed in the same period."  So the paper says that Palestinians kill Israelis, but in the case of (more) Palestinians killed by Israelis the paper phrase the killing simply as "they have been killed".  By whom? We don't know.