"I'm sorry."
The Mikaelson had to see it with his own eyes. Katerina was said to be dead - but only a firm, rock solid grave stone would confirmed it. Along with that information Klaus had been told that the incident had occured 3 years ago.
Nevertheless, he actually did feel somehow remorse for all those years chasing her for his own purposes. If it hadn't been for him, she wouldn't have possibly turned out to be so devilish - but there was no turning back now. Klaus simply observed the stone frowning; it was real.
"--Well... let's assume you're laughing at me from wherever you are Katerina--" Klaus was cut off by a familiar voice, that brought a simple sarcasm to its tone, or maybe it was just her way. Despite that fact, he turned in shock, after what he'd read and seen Klaus didn't believe - it was his mind playing him. As usual. "This is not possible. You are d e a d ."