dragnet
noun [ C ] uk/ˈdræɡ.net/ us/ˈdræɡ.net/
（警方的）撒网行动，抓捕方案
a series of actions taken by the police that are intended to catch criminals
The police have widened their dragnet in their search for the killer. 警方已经把搜捕杀手的网张大了。
拖网，拉网
a heavy net that is pulled along the bottom of a river or area of water when searching for something