Criminal Law Questions? Ask a Criminal Lawyer.
What's your question regarding this situation?
You're between a rock and a hard place. Welfare wants to verify your income for that year. If you don't provide it, they are not going to go away. They will continue to investigate you and draw conclusions based on what they may already suspect.
If, on the other hand you do provide your tax returns, there are potential problems there as well. Did you report your self employment income to the IRS? How small of a self-employment income is "quite small?"
The possible repercussion is that the government won't see this as a mistake and that you could be charged with welfare fraud. You need a local welfare fraud lawyer to assist you with the affidavit. You don't want to compound the problem by swearing to anything false. At the same time you don't want to make unnecessary admissions.
I'm going to opt out of this question because there's a tax issue here too and it's somewhat out of my ballpark. It's not yet and hopefully won't be a criminal law issue. Another lawyer will pick this up and you'll get an email when that happens.
No need to respond to me as that will lock the question, and no need for you to rate my service since I've not been able to provide you with a full answer.
A different Professional here.
I concur with the information already provided to you by my colleague. However, I will add one thing: you need to get a tax preparer or CPA to amend your tax return to reflect the correct income. Then submit the amended return to the welfare department.