Who Counts as Victim and Thief in the Law of Kidnapping

It was taught: "if a man is found stealing a person" (Deuteronomy 24:7): whether one steals a man, or steals a woman, or a convert, or a freed slave, or a minor, he is liable. If he stole him but did not sell him, or sold him but the victim was still in his domain, he is exempt. If he sold him to his own father, or to his brother, or to one of the relatives, he is liable. One who steals slaves is exempt. A reciter taught before Rav Sheshet. He said to him: I teach it thus: Rabbi Shimon says, "from his brothers," meaning he is not liable until he takes the victim out of the domain of his brothers; yet you said he is liable? Teach instead: exempt. For the anonymous Sifrei follows Rabbi Shimon. One who steals his own son: Rabbi Yochanan ben Beroka holds him liable, and the sages exempt him. What is the reasoning of the sages? It is written "and he is found in his hand shall surely be put to death," excluding one already found present. Therefore those teachers of young children, and those who instruct the rabbis, are like ones already found in his hand, and are exempt. If one stole a person who is half slave and half free: Rabbi Yehudah holds him liable, and the sages exempt him. Rabbi Yehudah reasons: "from his brothers" excludes slaves, and "the children of Israel" excludes one who is half slave; this is a restriction after a restriction, and a restriction after a restriction serves only to expand. And the sages hold: "from his brothers" to exclude slaves does not imply itself to them, for he is a brother in the commandments; "the children of Israel," "from the children of Israel," one phrase to exclude slaves and one to exclude one who is half slave.