Is an investment a debt?

An agreement was signed between four people. In that agreement, we represented the first party. The second party has used the cheques of our company (sole proprietor) to file a cheque bounce case on us, hiding the fact of the agreement in the complaint made. The second party invested a sum of 15 lakhs and clearly mentioned in the agreement that at anytime that person can get out of the agreement and we will have to pay him the investment amount along with 10 percent surplus and profit (if any). There is also a point in the agreement where the loss will be shared as 25 percent each. This agreement was done with regard to a tender, but the business failed completely. Now the second party who has not yet given any notice of getting out of the agreement,has put upon cheque bounce case solely on the first party. So I want to know if investment from second party is a debt? Doesn't it become null and void?