George could feel the presence of the intruders quite well, and he knew exactly where they hid, but he chose to ignore them. In as much as he'd like to put a stop to them, he wasn't exactly a fan of fights and violence. Besides these men hadn't caused any harm to any of the cathedral's inhabitants for now.
It was odd, but he could almost swear he'd sensed Nicholas, but he couldn't be sure. He had seen Nicholas's dead body, and he was the one who confirmed it's authenticity. He trusted Hollister, and he had no doubts about him carrying out his mission.
The intruders were doing a good job at keeping the aura and energy in concealed. He chose not to bother himself nor his enemies. If he tries to find out their identities it would inevitably lead to an all out battle and he wasn't prepared for that. As long as they weren't causing any harm or making any wrong moves, he would ignore them like they never existed.