“Can’t they?” queried Cranston. “Have you ever tried it?”
Margo shook her head.
“It’s easy,” assured Cranston, “when you have a mile or more of buildings to pick from. Lots of them have open roofs where the tenants go in hot weather and their friends come up to visit them. Some buildings have service elevators and there are all sorts of excuses such as delivering packages, that would allow a trip to the top floor.
“Besides, those flashes weren’t all from top floors; a lot of them were just high up. They didn’t have to come from apartments; but from corridor windows that opened in the right direction. So you can be quite sure that none of those lights really represented the Canhywllah Cyrth.”
“Particularly since the banshee didn’t reappear,” agreed Margo. “But you said some of the blinks were messages. How did you know?”
“I worked at decoding some that flashed the other night,” Cranston explained. “The first glimmers that showed this evening fitted with the code. It said something about the Parkside House and there was another word, rather hard to make out.”
“Have you any idea what it was?”
“I have now. The word was a name. It spelled Ames.”
Margo’s eyes widened.
“You mean the disappearance of Winslow Ames was ordered by those signals, Lamont?”