Sadat el-Kadasa, a convict in the Nitzan Prison in Ramle, has admitted that he killed another prisoner yesterday. He claimed he did it because his late cellmate pushed and cursed him. Sadat is one of three 23-year-old triplets - the others are named Carter and Begin - whose Israeli-Arab father named them after the signers of the Camp David peace treaty between Israel and Egypt. All three were arrested two months ago for drug-related crimes, and were supposed to be released yesterday.