There is a category of land fraud in this market that requires no forgery ring, no corrupt official and no sophistication whatsoever. It requires a printed document and image editing software. A name gets changed. A subsisting mortgage entry gets erased. The document is then handed to a buyer who has no particular reason to doubt it.
The defence is procedural, not forensic
You do not need to be able to detect a doctored document. You need to never rely on one. The encumbrance certificate is available to be pulled independently through Kaveri 2.0, at a cost measured in tens of rupees. The RTC is available as a digitally signed i-RTC through the Bhoomi portal. Both take a day or two. Neither requires the seller's cooperation.
What the record actually shows
The EC shows the transaction history registered against the property. The RTC shows the current revenue position — who the record says holds it, and what the extent is. The e-Khata shows the municipal position. Each answers a different question, and a gap between any two of them is the finding, not an inconvenience.
The online record does not reach all the way back
Post-2004 encumbrance records are generally available online in Karnataka. Earlier periods require a manual search at the Sub-Registrar office. A thirty-year search therefore has an online component and a physical component, and a diligence report that quietly omits the physical component has not done a thirty-year search.
The mutation timing tell
One pattern worth internalising: a mutation recorded unusually recently, shortly before a sale is proposed, is worth cross-verifying independently at source. It is frequently innocent. When it is not, it is the whole problem.