Don't talk to the police or the IRS. They are never aligned with your interests, and whether you get a reasonable person or someone who just loves to ruin your day is random.
If our local IRS equivalent contacted me "to clear something up", I'd defer them to my tax consultant in all cases. Assuming good faith with state employees is often a costly mistake.
One good friend got audited five years in a row; maybe the local bureau chief was just sure he was up to something. The last time they were writing a check to him, it was going to be for less than $2, and the agent asked if they really wanted it — "Of course I damn well want you to write that check!".
I've had a career mostly in small businesses, and always had a CPA do it with never an audit. I strongly suspect that it not only likely gets me more proper deductions that I'd miss, but also gets a lot of points in avoiding an audit, since the CPA is also putting their license on the line by signing it. I'd recommend the practice, just find a good one who charges flat rate (they do exist, just takes some looking).
Basically, give them only what they ask for and exactly what they ask for.
If no one sees something, it doesn't exist, right?