They walked quickly, heads down against the wind, eager for shelter. The walkway ran on another hundred yards or so past the weir, paralleling the bank, then turned abruptly to the left and vanished into the trees.

The respite proved brief, the belt of trees narrow, but it allowed them to catch their breaths before they came out into the open again and saw the lock before them. Yellow scene-of-crime tape had been stretched along the concrete aprons on either side of the lock, but not across the sluicegates themselves. To their right stood a sturdy red-brick house. The French-paned windows were symmetrical, one on either side of the door, but the one nearest them sported such a thatch of untrimmed green creeper that it looked like a shaggy-browed eye.

As Kincaid put a hand on the tape and bent to duck under it, a man came out the door of the house, dodging under stray twigs of creeper, and shouted at them. “Sir, you’re not to go past the tape. Police orders.”

Kincaid straightened up and waited, studying the man as he came toward them. Short and stocky, with gray hair bristle-cut, he wore a polo shirt bearing the Thames River Authority insignia, and carried a steaming mug in one hand. “What was the lockkeeper’s name?” Kincaid said softly in Gemma’s ear.

Gemma closed her eyes for a second. “Perry Smith, I think.”

“One and the same, if I’m not mistaken.” He pulled his warrant card from his pocket and extended it as the man reached them. “Are you Perry Smith, by any chance?”

The lockkeeper took the card with his free hand and studied it suspiciously, then scrutinized Kincaid and Gemma as if hoping they might be impostors. He nodded once, brusquely. “I’ve already told the police everything I know.”

“This is Sergeant James,” Kincaid continued in the same conversational tone, “and you’re just the fellow we wanted to see.”