Keeping a gun in a felon's home?

So I am turning 21 very soon. I plan to buy a pistol on my birthday. The issue is that I am currently still living with my parents, one of which is an ex-felon (been out of prison for over 8 years, was in for just over 3). I know this varies state to state, but I just cannot find any information on the subject. If I keep the gun in a lock box, with the only key being on me at all times, am I able to keep the gun in the same house as the ex-felon? A couple of points you might need:

Living in Missouri
It was a violent felony (not involving any sort of gun though)
I am squeeky clean, and if I was living in my own place wouldn’t even be asking.

Can anyone help?

P.S. While all information is appreciated, this isn’t a, “do you believe I should have a gun” question. So please don’t give me overly opinionated statements not relating to my question.