dragnet

nouns

a system of coordinated measures for apprehending (criminals or other individuals)
"caught in the police dragnet"
dragnet
is a type of (narrower)
a group of independent but interrelated elements comprising a unified whole
"a vast system of production and distribution and consumption keep the country going"
scheme, system
a conical fishnet dragged through the water at great depths
dragnet, trawl, trawl net