Deed of Sale;Part of it Unrecovered

Hi! Nice to know it's sort of interactive here. Anyway my concern actually is about deed of sale. My father-in-law bought different parcels of land(he is a lawyer;deceased). We have the deed of sales. For this I know(correct me if I'm wrong)that it's good as title. Now there's this parcel of land that my father-in-law owned.When he died unexpectedly,that's the time things got messed up. He owned that parcel for 20 years. Now a case in progress. No one has ever impugned this. My question is: should we worry about this?what should be done since that deed of sale was misplaced?How do we defend that?Please help!

If you could atleast remember the person who notarized the deed of sale, perhaps you may try to find out if the notary public retained a copy. By the way, what was case you mentioned that is in progress?

the case in progress is unlawful detainer. The defendants seemed to be diverting the case to asking about ownership. i am very well aware that ownership will ONLY be discussed for limited purposes but never build the case out of it. The question is not the ownership.In fact I have informed their lawyer that if they would like to elaborate on that they can file it in a different court. But right now the question is not about ownership but who has the right to possess. thanks for answering..