Definition
To gradually close in on someone, especially a criminal, making their capture more likely.
收緊包圍網（特別是對犯罪者）
The police are tightening the net in their attempt to capture the fugitive.
警方正在收緊包圍網，試圖逮捕逃犯。
As the investigation deepened, they began to tighten the net around the suspect.
隨著調查深入，他們開始收緊對嫌疑人的包圍網。
The prosecutor stated that they were tightening the net on the criminal organization.
檢察官表示他們正在收緊對犯罪組織的包圍網。