Question about a Silent Investor?

[Sean Sloop]

Hello BP, 

I have a potential legal question. 

If I have a relative that wants to invest some money into a property I am buying, but I do not want their name on any part of the property, is there a legal problem to be concerned?

For Example, if I buy a 100k home with a 20k downpayment. My relative gives me 10k for 50% equity. He is not on title or partner in LLC or anything. Is this a legal issue?

I will likely contact a lawyer if we officially agree, but thought I would pose the question here while it is just a thought. 

Thanks for the time!

Sean