https://en.wikisource.org/wiki/Popular_Science_Monthly/Volume_81/November_1912/Negroes_Who_Owned_Slaves

Judge William Gasken, who owned the man of whom we have just told, was thrice married, one of his wives being a daughter of Colonel McClure, of New Bern. After his death, one of the slaves, Jacob, became the property of Mrs. Gasken. This Jacob's wife was a free woman, and they had a son Jacob, then a young man and free, of course, as the child of a free woman. Aided by his mother's efforts, he managed to purchase his father at a very reasonable price as negroes were then held. All went smoothly for awhile, when young Jacob did not act as his father thought he should and his parent reproved him with fatherly love. Young Jacob was so disgruntled that he went off to a negro speculator named John Gildersleeve, who was from Long Island and was then in New Bern. This trader bought the father at a high price and at once sent him off south. Young Jacob afterward boasted that "the old man had gone to the corn fields about New Orleans where they might learn him some manners."

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There was a negro named Nat Butler who lived near Aberdeen, Harford County, Md., who owned a small farm and bought and sold negroes for the southern trade. This sharp and noted fellow would persuade a slave to run off and hide for a few days at a place prepared by Butler, who would in the meantime see the master of the runaway and learn the price he would take for him. If the owner had little hope of recovering his slave and so placed the price low, Nat would buy him and resell him to slave dealers who knew Butler's rendezvous for hidden negroes. His conduct became so notorious that he lost the confidence of slave owners and respect of negroes, who several times tried to murder him.