A craftsman does not establish a chazakah in an article known to have belonged to someone simply by having it in his possession.
Said Rabbah, “This is only true when the original owner gave the
craftsman the article in the presence of witnesses. But if not, the
craftsman could have denied receiving the article altogether, and is
believed on the strength of the “Why would he lie?” argument.
Said Abaye, “If so, he should be believed even if there were witnesses,
for had he wanted to lie, he could have said that he returned the
article.”
They differ about the following question: if someone deposits an
article with his fellow with witnesses, does the custodian need to
return it also in the presence of witnesses? The accepted answer is
“no,” which means that Abaye's ruling prevails.