How can I use my U.S. income as source of funds for EB-5?

It depends on how you received the funds from the California company. You will need to have your attorney review these details to determine if your capital meets the "lawful source of funds" requirement.

If the money you earned from the U.S. business was paid out to you as a dividend from profits, and if you paid taxes on it, you can use that money for an EB-5 investment. But if the money came out to you as salary for working, and if you did not have a work visa, they will not count this money as from a lawful source.

It appears that you worked without authorization in the U.S. Regardless of where you house your money, you still have to document its source.

The funds you earned in the United States in violation of U.S. laws likely will never be considered lawful for EB-5 purposes, even if those funds were transferred back to your home country. The transfer does not change the ultimate source of the funds, which was unlawful.

The I-526 petition must include an explanation and documentation of the source of the funds which are invested. If you transfer the money back to your home country, then you still must explain and document that the source of the funds is the business in California.

You have to show a lawful source of funds and yes, you can treat your earnings from your own business as a lawful source of funds. It is possible that the Immigration Service would raise questions about whether or not you were work authorized at the time you were earning such funds, although technically that is not an issue with respect to adjudicating the EB-5 petition. You may earn funds in a business that you own and is operated in the U.S. and visit the U.S. in B-1 Business status from time to time in conjunction with the operation of your business. However, if you "operate it", that appears to be unauthorized employment. Sometimes there is a fine line between supervising and checking up on the investment and being employed in it. Even if you were to transfer the money back to your own country and then re-transfer it, you would still have to be able to document the original source of such funds.

It would be difficult to prove "lawful source of funds" if you operated a business and/or worked in the U.S. without authorization.

It is possible to invest using your California company as the source of funds. However, this would require more facts in order to ensure it is lawfully acquired source. For instance, information such as whether you were running the business overseas, whether you engaged in productive employment, whether you filed the appropriate tax returns, etc. would be relevant. I will need further information to make a proper determination.

It depends on how the funds were earned. If the funds are earned as a dividend or profit distribution from a US company, then USCIS should not question it. Receiving passive income from a US company in form of dividends or profit distribution does not require a work visa. If the income was earned as a salary, then it would violate a tourist visa status and cannot be used. Transferring the funds to another country will not help, because the source of the funds still has to be explained and the path of the funds has to be traced.

Transferring the funds to your home country will not help; it does not change the source. Foreign nationals can own business in the US thus having a business in the US does not, by itself, violate any immigration laws. You should have an EB-5 attorney evaluate the specifics of your case.