What I am saying is that a defense attorney does not typically want a guilty client to confess to him. Because then the attorney cannot put anyone on the stand that conflicts with that knowledge.
So, in my example, if the atty knew the client was guilty, then he would obviously know the alibi was false. In effect, he would know that any alibi was false. See the problem there?
So it is better for the client NOT to admit his guilt to the attorney so the attorney can believe in his innocence and put up a full defense.
ETA; It does not matter if it can be proven to be a fact or not at trial. It is against the law for an attorney to knowingly put false testimony into the court record.