So there was a Roman invasion in which Julius was the leader that resulted in the burning of the library. He later contended that his guys didn’t do it, maybe, maybe not. But he was there when it happened and he was leading the invading force. It may have been a bibliophobic Alexandrian that used the opportunity to destroy the library. I guess we’ll never know.The point is, the Library wasn't destroyed -- it remained in use for hundreds of years thereafter. Had it burned, Julius Caesar would have discussed it, since the Library wasn't located on the wharves, but in the very citadel he and his troops were occupying.
Like I said, I’m always ready to learn and an avid reader. What are your sources.