massive manhunt
先ほどと同じ記事からもう一つ表現を拾います。
Manhunt underway for bombing suspect; one suspect dead
Less than seven hours after the FBI releases images of Boston bombing suspects, one is killed in a shootout with police, the other remains the target of a massive manhunt
BOSTON — The city and its suburbs are in lockdown this morning as a massive manhunt intensifies for the surviving suspect in the Boston Marathon bombing. The search comes just hours after the suspect's older brother was killed in a dramatic shootout with police in nearby Watertown, authorities said.
http://www.usatoday.com/story/news/nation/2013/04/19/suspect-in-custody-newspaper-says/2095845/
ここで注目するのはmassive manhunt という表現です。「大規模な犯人捜査」を、massiveとmanhuntを使ってこのように表現できることは知りませんでした。しっかりとおさえておきたいと思います。(Jakie)