“Indeed they could,” Master Sean agreed.
Lord Bontriomphe looked expectantly at Lord Darcy.
“Very well,” said Lord Darcy with a smile, “let us proceed to try that theory by what the geometers call, I believe, the reductio ad absurdum. Imagine the scene. What happens?”
He gestured toward the body on the floor. “Sir James is stabbed. Our sorcerer-murderer — if you’ll pardon the double entendre — goes to the window. He opens it. Then he steps up to the sill and steps out into empty air, levitating himself as he does so. Then he closes the window and proceeds to cast a spell which slides the bolts into their sockets. When that is done, he floats off somewhere — up or down, it matters not which.” He looked at Master Sean. “How long would that take?”
“Five or six minutes at the least. If he could do it at all. Levitation causes a tremendous psychic drain; the spell can only be held for a matter of minutes. In addition, you’re asking him to cast a second spell while he’s holding the first. A spell of the type that was cast on this room is what we call a static spell, my lord. It imposes a condition, you see. But levitating and the moving of bolts are kinetic spells; you have to keep them moving. To use two kinetic spells at the same time requires tremendous concentration, power, and precision. I would hesitate, myself, to try casting a window-locking spell with a thirty-foot drop beneath me. Certainly not if I were in a hurry or distracted.”
“And even if it could be done, it would take five or six minutes,” Lord Darcy said. “Bontriomphe, would you mind opening the other window? We haven’t tested it yet.”
The London investigator drew back the bolt and pushed the window open. It groaned audibly.
“What do you see out there?” Lord Darcy asked.
“About nine pairs of eyes staring up at me,” Lord Bontriomphe said.
“Exactly. Both windows make a slight noise when they are opened. That noise is quite audible in the courtyard below. Yesterday morning, Sir James’ scream was clearly audible through that window, but even if it had not been — even if Sir James had not screamed at all when he was stabbed — the killer could not have gone out through that window without being seen, much less hovered there for five or six minutes.”
Lord Bontriomphe pulled the window closed again. “What if he were invisible?” he asked, looking at the little Irish sorcerer.
“The Tarnhelm Effect?” asked Master Sean. He chuckled. “My lord, regardless of what the layman may think, the Tarnhelm Effect is extremely difficult to use in practice. Besides, ‘invisibility’ is a layman’s term. Spells using the Tarnhelm Effect are very similar in structure to the aversion spell you met at the door to this room. If a sorcerer were to cast such a spell about himself, your eyes would avoid looking directly at him. You wouldn’t realize it yourself, but you would simply keep your eyes averted from him at all times. He could stand in the middle of a crowd and no one could later swear that he was there because no one would have seen him except out of the corner of the eye, if you follow me.
“Even if he were alone, you wouldn’t see him because you’d never look at him. You would subconsciously assume that whatever it was you were seeing out of the corner of your eye was a cabinet or a hatrack or an umbrella stand or a lamppost — whatever was most likely under the circumstances. Your mind would explain him away as something that ought to be there, as a part of the normal background and therefore unnoticeable.
“But he wouldn’t actually be invisible. You could see him, for instance, in a mirror or other reflecting surface simply because the spell wouldn’t keep your eyes away from the mirror.”
“He could cast a sight-avoidance spell on the mirror, couldn’t he?” Lord Bontriomphe asked. “That’s a static spell, I believe.”
“Certainly,” said Master Sean. “He could cast a sight-avoidance spell on every reflecting surface in the place. But a man has to look somewhere, and even a layman would get suspicious under circumstances like that. Besides, to anyone with even a half-trained Talent, he’d be detectable immediately.
“And even supposing he did make himself invisible outside that window, do you realize what he would have to do? Now you have him juggling three spells at once: he’s levitating himself; he’s making himself ‘invisible’; and he’s closing that window.
“No, my lord; it won’t do. It just isn’t humanly possible.”
Lord Darcy let his gaze wander over the room. “That’s settled, then. Our killer did not go out those windows either by thaumaturgical or by ordinary physical means. Therefore, we—”
“Wait a minute!” said Lord Bontriomphe, his eyes widening. He pointed a finger at Master Sean. “Look here; suppose it happened this way. The killer stabs Master Sir James. His victim screams. The killer knows that you are outside the door. He knows he can’t get out through the door. The windows are out, too, for the reasons you’ve just given. What can he do? He uses the Tarnhelm Effect. When I come busting in here with an ax, I don’t see him. As far as I’m concerned, the room is empty except for the corpse. I wouldn’t be able to see him, would I? Then, when the door’s open, he walks out as cool as an oyster, with nobody noticing him.”
Master Sean shook his head. “You wouldn’t notice him; that’s so. But I would have. And so would Grand Master Sir Lyon. We were both looking in through that hole in the door, and a man can see the whole room from there — even the bathroom, when the door to it is open.”
Lord Bontriomphe looked at the bathroom through the open door. “No, you can’t. Take a look. Suppose he were lying down in the tub. You couldn’t even see him from in here.”
“True. But I distinctly recall your looking down directly into the tub. You couldn’t have done that if a killer using the Tarnhelm Effect were in it.”
Lord Bontriomphe frowned thoughtfully. “Yes. I did. Hm-m-m. Well, that eliminates that. He wasn’t in the room, and he didn’t leave the room.” He looked at Lord Darcy. “What does that leave?”
“We don’t know yet, my dear fellow. We need more data.” He stepped over to where the body lay and knelt down, being careful not to disturb anything.
Master Sir James Zwinge had been a short, lean man, with receding gray hair and a small gray beard and moustache. He was wearing a neat, fairly expensive gentleman’s suit, rather than the formal sorcerer’s costume to which he was entitled. As Bontriomphe had said, it was difficult to see the stab wound at first glance. It was small, barely an inch long, and had not opened widely. It was further obscured by the blood which covered the front of the dead magician’s clothing. Nearby, a black-handled, silver-bladed knife lay in the pool of blood on the floor, its gleaming blade splashed with red.
“This blood—” Lord Darcy gestured with his hand. “Are you absolutely certain, Bontriomphe, that it was fresh when you broke into this room?”
“Absolutely certain,” Bontriomphe said. “It was bright red and still liquid. There was still a slight flow of blood from the wound itself. I’ll admit I am not a chirurgeon, but I am certainly no amateur when it comes to knowing something about that particular subject. He couldn’t have been dead more than a few minutes when I first saw his body.”
Lord Darcy nodded. “Indeed. The condition of the blood even now, under the preservation spell, shows a certain freshness.”
He gestured toward a key that lay a few feet away from the body. “Is that your key, my lord?”
Lord Bontriomphe nodded. “Yes. I put it there to mark the spot when I picked up Sir James’ key.”