Exodus 22:7

if the thief be found, he shall restore two for one. If the thief be not found, the master of the house shall be brought before the judges, and shall swear that he hath not put forth his own hand upon the property of his neighbour.

WHETHER HE HAVE NOT PUT HIS HAND UNTO HIS NEIGHBOR’S GOODS. In the opinion of Rashi this means that the guardian is to come before the judges to swear that he has not put his hand to his fellow-man’s goods [i.e., that he is not guilty of embezzlement]. The correct interpretation is that he is to come before the judges to swear that it was stolen and thus substantiate his claim, but he can only swear thus if he did not put his hand to make use of his neighbor’s goods, for he who puts to his own use what had been left in his keeping is answerable for it as if he were a robber, and is liable to make restitution even if it was lost through an unavoidable accident.

'אם לא ימצא הגנב ונקרב וגו, the words אם לא ימצא are understood by our sages (Baba Kamma 63) as meaning that the trustee claimed the animals had been stolen, while in effect he himself had stolen them. If he swore an oath before the judges that he was not involved in their disappearance and he is found afterwards to have perjured himself then he must compensate the owner by paying him twice the value of the “stolen” animals. Personally, I will explain the verse in terms of the plain text, although this does not reflect the halachah. The words אם לא ימצא הגנב ונקרב בעל הבית אל האלוהים, refer to the trustee. שלא שלח ידו במלאכת רעהו, he swears that he personally had not been guilty of appropriating any of his fellow man’s goods but that those that are missing were stolen. On the basis of such an oath he is exonerated from all responsibility.

אם לא שלח ידו, if the trustee had done anything illegal with the object entrusted to him for safekeeping he is responsible even for accidents happening to said items.