That is false.
If you murder me and are never apprehended, tried or convicted, you have still committed the felony.
And, as you have committed a felony, you are a felon...not a convicted felon...but a felon just the same.
If I allegedly murder you then I have to be convicted. There are plenty of people walking around right now that "murdered" someone and are not called felons simply because they have not been tried and convicted of a felony.
What they are called by the public is irrelevant, as is their conviction.
If they committed a felony, they are felons, convicted or otherwise.
Just like a liar. I can't call you a liar unless I have proof that you lied. But if you lied, you are a liar, caught or otherwise.
If there is proof Brown committed a felony, he is a felon regardless of conviction.
And there is proof in law that this is a fact.