Im 99.99% positive that OP has told NO ONE the truth.
In fact, I suspect the very LAST people he would ever tell the truth to would be Carl and Aimee - he values their love and respect more than anyone on earth. He simply could not withstand their possible revulsion, hatred and rejection. Yes, theyre siblings and yes, theyre extremely close but even close siblings dont always agree and see eye to eye ... or approve of each others dealings. Murder is a line the vast majority of humans do not cross - their friendship, love, respect and support is never tested by same. To confess to Carl and Aimee, OP would have to be certain they share the same exact values and mind set, be absolutely certain of their response (who has that kind of guarantee?) - but when it comes to murder, that is truly the ultimate test. OP could never really be 100% certain about even Carl and Aimee.
Is it possible he confessed to Carl and Aimee? Yes.
Is it probable? No.
OP is already a social pariah - he cannot confess and take the terrible chance of becoming an outcast in his own family.
Oscar Pistorius must be a very lonely and yes, alienated man - imprisoned with the TRUTH inside his head.
Then again, playing devils advocate ... perhaps hes already confessed the truth to his immediate family.
After all, the rotted apple doesnt fall far from the rotted tree.