Commentary for Bava Metzia 71:5
שוכר בחטאת ושואל באשם כגון שמתה כדרכה ואמרו מתה מחמת מלאכה שוכר דבין כך ובין כך מיפטר פטור חייב בחטאת שואל דמיחייב במתה כדרכה וקא פטר נפשיה במתה מחמת מלאכה באשם
is liable to a sin-offering, and the borrower, who is responsible in both cases, is [likewise] liable to a sin-offering. 'Sometimes both are liable to a guilt-offering.' E.g., if it was stolen, and they maintained that it had died of its work. Thus both deny monetary liability, since in fact they are responsible [for theft], whilst they free themselves. 'The hirer is liable to a sin-offering and the borrower to a guilt-offering.' E.g., if it died a natural death, and they maintained that it had died of its work. The hirer, who is free [from responsibility] in both cases, is liable to a sin-offering; the borrower, who is liable if it dies a natural death but frees himself with [the plea that] it died of its work, to a guilt-offering. 'The hirer is liable to a guilt-offering, and the borrower to a sin-offering.' E.g., if it was Stolen, and they maintained that it had died naturally. The hirer, who is liable for theft and loss but frees himself with [the plea,] it died naturally, incurs a guilt-offering; the borrower, who is responsible in both cases, a sin-offering.