U already know the process.
Since it is a link document, have a declaration from the owner/previous owner about the same nt used for lien/mortgag.
How old is the doc and after that how many transfer took place and how many yrs gone by is also relevent.
If local police not taking the complaint, u can write to SP/CoP. See if u get certified copy or an entry confirmation from the Registrar off.
Note org is org. If u r selling, check with purchaser as to on what he will be satisfied.