Question
Recently my expensive ($1,500) electric bike was stolen. Figuring that perhaps the thief would try to sell the bike I carefully followed the advertisements for used bikes. After a few days I found an advertisement for a bike that described my bike perfectly. Confident that this was my bike, I contacted the one who placed the advertisement and arranged to come and check out the bike. Since I was scared to deal with the thief myself, I hired a strong, awesome-looking person to accompany me to check out the bike. When we arrived, I saw that indeed this was my bike and my companion began discussing purchasing the bike. While discussing the purchase, my friend purposely walked the thief away from the bike. When they were sufficiently distanced from the bike, I quickly took the bike, locked it the trunk of my car and my friend ran into my car and we drove off. When we got home, I noticed that the thief had spent about two hundred dollars on improvements to my bike in order to sell it, which is about the amount I spent in order to retrieve my bike. The improvements that he made were that he installed a brand-new battery and a small repair. The reason he needed the new battery was because at the time he stole the bike, the battery was being recharged in my house so he did not get my battery. Do I owe any money to the thief for the improvements that he made to my bike?
Answer
Your question involves two issues. The first issue is whether a thief is entitled to reimbursement for improvements that he made to an item that he stole. The second issue is whether a thief is liable for his victim's expenses in order to retrieve his stolen property.
The first issue is ruled by the Shulchan Aruch (CM 372, 3) based on the Gemara (BM 14B). The ruling is that the thief is entitled to the lesser of: 1-his cost and 2-the value added to the stolen item. His cost is valued at the cost of the raw materials plus payment for his work which is calculated as the cost of the cheapest labor that can accomplish the task.
This ruling is somewhat strange since it digresses from the general rule. Since the thief was obviously not hired by his victim to improve his property, the status of the thief in improving the stolen item is that of a yoreid shelo birshus-one who works for someone without having been hired or given permission to perform the task. The usual rule is that the compensation that such a worker is entitled to depends on the nature of the improvement of the worker. If the improvement of the yoreid was not necessary, then the compensation is as described above. However, if it was a necessary improvement, then the compensation is the amount that one would actually have to pay to achieve the improvement that the yoreid made. This includes both the cost of the materials used and the amount one would be pay to a skilled worker to perform the task.
The Rishonim discuss why a thief is not compensated in the usual manner and they offer two approaches. The approach of the Ra'avad (BK 95B) is that it is a fine that was imposed upon thieves. However, the consensus of the Rishonim is that this is an application of an important general principle concerning the laws of yoreid. This principle (See e.g., Ran BM 39B) was espoused by the Ramban, who derived it from the ruling of the Gemara concerning thieves. The principle is that if one improves someone else's property without intending to be paid by the owner of the property, the owner is not liable for the full amount that it would actually cost to accomplish what the yoreid accomplished but just the cheapest way to accomplish it.
Besides the case of a thief who improved stolen property, this rule applies to a case which is discussed in the Gemara (BM 39B) concerning an heir who improved his inheritance, thinking that the entire inheritance was his, but later discovered that he had a brother. Here as well, the Gemara rules that the long-lost heir is not required to compensate his brother for the full amount that it would cost to accomplish the improvement. These Rishonim explain that the rationale is that when the heir improved his inheritance he did not expect to be compensated by a newly-discovered brother.
Applying this rule to your situation, the thief is entitled to be paid for the improvements that he made to your bike unless you inform him that he may reclaim what he invested in your bike and you don't use his improvements (known as tul eitsecho veavonecho). However, if you do not do this, you owe him the lesser of: his costs or the value added to your bike. Often these two amounts are the same. In your situation they are not since he bought a new battery which you do not need. Since you do not need an extra battery, the value added to your bike is only the resale value of the new battery which is significantly less than the cost of a brand-new battery.
Having determined that you owe the thief money, we must determine if you are entitled to offset your debt by what it cost you to retrieve your bike.
There is no Gemara or ruling of SA that rules directly on this issue. One indication is a ruling of the SA (CM 14, 5) concerning someone who refused to have his case adjudicated by beis din, thereby causing his counter-party expenses in order to have justice served. Based on a responsum of the Rosh (Klal 73), SA rules that the plaintiff is entitled to reimbursement for all of his expenses and the Gro explains that the reason is because these damages, though causative, are classified as garmi. Thus, the expenses that the thief caused you in order to bring justice to your thief would also seem to be garmi for which you are entitled to reimbursement.
Another ruling of the SA that bears on your question concerns a thief who took something that he stole to a different place. Based on the Gemara (BK 104), SA (367, 1) rules that if the thief never denied or swore that he did not steal the object, the thief need not physically return the object and he can simply inform his victim where he may retrieve the stolen object.
The ruling that the thief is not obligated to fully undo the damage that he caused his victim is surprising. The Sema (note 2) explains that this an enactment of the Rabbonon to encourage thieves to repent their misdeeds. To this end, the Rabbonon waived the Torah requirement to physically restore the stolen object to its owner. Based on this opinion, it follows that if a thief did not repent, the requirement to physically return the stolen object remains in force.
One can prove this from another enactment that was made in order to encourage thieves to repent. This enactment was that in spite of the Torah requirement for thieves to return or pay for everything they stole, the Rabbonon enacted that if a habitual, well-known thief repents but no longer has all the objects that he stole, the victims must refuse the thief's offer to pay for the value of the objects that he stole. In this case the Ramo (366, 1) states explicitly that if the thief did not repent and the victim was forced to sue for repayment, the thief must pay and the victim can demand payment in full.
Thus, we see that enactments that were made in order to encourage thieves to repent only apply to those who actually repent. In your case, the thief did not repent. Therefore, according to the Sema the thief was required to return the bike to you and by not having done so he forced you to spend money. Therefore, it follows that he is liable for your expenses as garmi.
The Shach (367, 2) disagrees with the Sema and maintains that there was no waiver involved in the exoneration of the thief from the requirement to return the stolen object. It might seem that he maintains that the thief is not required to bring the stolen object to his victim. However, in another place (386, 8) the Shach rules explicitly that if a thief threw the object that he stole into the water, he is required to physically retrieve it.
The Pischei Choshen (Geneivo 4, footnote 11) resolves the apparent contradiction. He says that the Shach maintains that if a thief took the stolen object to a different place, he is required to physically return the stolen object to its owner. When he writes that the thief is not required to return the stolen object to its owner, he means that if the victim moved, the thief is not obligated to bring the stolen object to the owner's new location. The thief is only required to do so if he denied and swore that he never stole the object in question.
Thus, actually the Shach is more stringent with the thief than the Sema. Whereas the Sema maintains that a thief who repents is not required to physically return the stolen object because of an enactment, the Shach maintains that there is no enactment and he must return it. Only if the victim moved the thief is not required to follow him to his new location.
In a related case, the Nesivos (232, 10) (who follows the Sema's approach) rules that if someone snatched another person's object without intent to steal the object and brought it to a different place, he is required to pay to return the object to its original location. It is only for someone who intended to steal that the Rabbonon enacted that the thief is absolved from the requirement to physically return the stolen object. He explicitly writes that the requirement to pay is based on the laws of garmi.
Based on the above, you owe the thief for the improvements he made to your bike, but you can reduce your debt by the amount you needed to pay in order to recover your bike, perhaps canceling your entire debt or even leaving the thief with a debt to you. If you can at least cancel the debt to him, you may keep the new battery that the thief bought without paying the thief anything.
