Must a guilty defendant pay for court expenses and litigation fees according to Halacha?
Fees involved in the initial Din Torah: The losing party of a Din Torah is not required to reimburse the winning side for expenses involved. This applies even if he forced the winning party to come to court in a different city, [and there were traveling expenses involved]. If, however, the losing party refused to come to any Beis Din and the winning party had to pay expenses to enforce the losing party to appear, then the losing party is responsible to pay for all the expenses, [beginning from the time that he refused arbitration].
If the losing party lost the case in Beis Din due to what was revealed to be a fictitious claim, can he be held liable to pay the winning parties expenses?
Some Poskim rule that the losing party is only exempt from court expenses if his claim was accurate but simply did not find merit in court. If, however, his claim was discovered to be fictitious, and a blatant lie, then he is obligated to pay for court expenses of the winning party.
 Michaber 14:5; Tur 14; Tosafus Sanhedrin 31b; Rosh Sanhedrin 3:40; Mordechai based on Gemara
 Rama ibid; Maharik 11; Nemukei Yosef ; Maryu; Teshuvas Harosh 108
 Yeshuos Yisrael 14:5; Rav Zalman Nechemia Goldberg; See Rama 14:5 that if the defendant said that he would come to court and then did not show up that he must pay for expenses