Explore into the intricate process of investigating forgery cases, fraud, and financial crimes in California law offices. Find the right forgery expert witness for your case with ForensisGroup.In California, forgery is an offense that arises when you make, alter, or use a falsified document to commit fraud. Counterfeiting or forging the handwriting or seal of another person is a forgery. An Overview of California PC 115. PC 115 defines filing counterfeit or false documents as knowingly filing fake or forged documents with a public office.