pavement. Rutledge managed to kick it out of reach, then concentrated on subduing the boy, gradually forcing his body backward until the fight went out of him.

He was just reaching for the cap that half covered Billy’s face when he heard a constable’s whistle and the heavy thud of his regulation boots as he came pounding over the crest of the bridge.

Startled, Rutledge sent the cap flying into the darkness.

“Here, now!” the constable exclaimed as he got closer and took in the two men, a knife lying some two yards away. From his vantage point, Rutledge appeared to be the aggressor, and Rutledge’s attacker took swift advantage of it.

He screamed, “Don’t let him hurt me—he’s trying to kill me. Help me—”

The constable was there, catching at Rutledge’s shoulder, hauling him away from his victim, and for the first time Rutledge glimpsed the flushed and frightened face of a boy who looked eighteen or nineteen but for all his size must be no more than sixteen.

And then as the constable’s fist closed over Rutledge’s bleeding arm, his fingers just as quickly opened again.

“What’s this, then?” the constable demanded, stepping back. He was thin and middle-aged, an imposing figure with the light reflecting from the crown of his helmet, giving the impression he was taller than he was. “Is that your knife, or his?” he asked the boy.

In that split second of hesitation, Billy wriggled free of Rutledge’s grip and set off over the bridge, his feet flying. The constable looked from him to Rutledge, and Rutledge said rapidly, “I’m Scotland Yard. Rutledge, Inspector. Go after him, man.”

But it was too late. By the time the constable had collected himself and pelted after the suspect, he had turned at the bridge abutment and was lost in the darkness on the far side of the river.

The constable came back, breathing hard, to meet Rutledge halfway. “I’m sorry, sir—”

“So am I. His next victim might not be as lucky.” He gave the constable a description of the boy, including the false name, and added, “He’s frightened enough to be dangerous.”

“I didn’t get a close look at him,” the constable admitted. “But I’ll see word is passed on.” He gestured to Rutledge’s arm. “You’d best have that seen to, sir.”

The wound was beginning to hurt now. Rutledge warned, “He may not always choose this bridge.”

“Yes, sir, I understand that.” He shook his head as he bent to retrieve the knife. “A pity. Nothing here to tell us where it came from. Common enough, by the look of it.” He ran his finger along the edge. “And sharp enough to bone a chicken.”

“I’ll come to the station tomorrow to make a statement,” Rutledge told him. “Where are you? And what’s your name?”

“Lambeth Station. Constable Bishop, sir.” He grinned tentatively, adding as if it were a longstanding joke, “Though there are none in the family that I know of.”

Rutledge didn’t return the smile. He nodded and walked back to where he’d left his motorcar. The blood trickling down his arm to his hand left a trail behind him, and he thought cynically that it was too bad that the boy hadn’t cut his own arm instead.

Dr. Lonsdale, answering the summons at his door, was in his dressing gown and still knotting the belt. “It can’t wait until morning?” And then he noted the dark patch of blood on Rutledge’s sleeve. “Come in, then,” he said and led Rutledge directly to his surgery.

“It’s not deep,” the doctor informed him, turning to wash his hands after examining and then bandaging the wound, “but it will be sore enough for a few days. Be careful how you use it.” Accustomed to patching up men from the Yard, he added, “Providing infection doesn’t set in from the knife that did this.”

It was good advice. The next morning the arm was still sore and felt heavy, but he reported to the Yard, where news of events had preceded him.

Bowles said as they crossed paths in the corridor, “Constable Walker has reported that a week ago on the Lambeth Road a boy tried to rob a doctor returning from a lying-in. Someone came along, and the boy ran. But the description is similar. He claimed he had a knife, but neither the doctor nor his rescuer actually saw it.”

“So I wasn’t the first victim.” He had hoped that he was.

“In fact, there have been a number of robberies at knifepoint south of the river, but most victims hand over their money without any