He could follow a cold trail over hard ground and even over stones.

他能循着地面上甚至是石头上留下的淡淡的痕迹展开追踪。

youdao

The police followed the robbers to the airport but then the trail went cold.

警察追踪抢劫犯到了机场，但是后来却失去了他们的踪迹。

《牛津词典》

The pheromones evaporate quickly, however, so once all the food has been collected, the trail soon goes cold.

然而信息素挥发地很快，所以一旦食物搬运完毕，这条信息素路径就不复存在了。

youdao

The killer vanished into the night, leaving a cold trail behind him.

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He was tracked to Jordan and then, possibly, Syria before his trail went cold.

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After his indictment the FBI followed him through Illinois, Indiana and out west to Arizona, but the trail ran cold.

BBC: Eric Justin Toth