What are possible consequences for real estate property tax fraud

Property Tax Fraud: If I know that someone is taking advantage of the property tax system in a particular county, should I report it? I feel like it's my civic duty to do so, but I know these people and they do not like me. The basic problem is that the owner is using the over 65 claim and has been since 2003. She just turned 62. What would be the penalties for this? Isn't this a crime?