"You were always a terrible liar, Buffy. You never pay attention to what you and others say either. Ambrose kicked up a fuss the moment I mentioned it back in the shop and so I blew the power and cameras, locked the doors and knocked out the shopkeeper remember? The fuss he made was confirmation that he knew and that you had told him" Lucius had to wonder if Buffy would ever apply logic to her life. He doubted it to say the least, she was far too busy fighting everything to step back and notice things and how they worked. Like people. Like humans. She was too busy fighting to save them to step back and notice that they don't want saving.
Lucius wasn't sure he could bring himself to prove to her that Daniel was dead. He could easily do so, any one of his many secrets would do. He would only exchange her pestering for her wrath in revealing them. So he stayed silent.
"Perhaps you are right but I would not hesitate to hurt Ambrose if I thought it necessary"