Lyle was standing across an abandoned house and staring at it from the rooftop of another house. The house he was looking at was the one he had sent Saldin to, and it was also the place where the latter had died.
With how quickly Saldin died, Lyle knew that the organization he had worked for was the one to blame, but he just didn't understand why they had waited until he had come all the way here to kill him. They had either found some clues and sent someone to go after Saldin, which meant that the person was a very good tracker that was able to locate Saldin quickly and probably tried to interrogate the latter before killing him.
Thanks to Saldin being Lyle's servant, he would be unable to tell the latter anything, no matter how much they tried to torture him, so they probably killed him after seeing that there was nothing they could do to get information out of him.