Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: (CNN) -- How were inmates inside a Texas prison allegedly able to make cell phone calls, plot crimes and acquire drugs? With the help of 17 former corrections officers who once worked at the prison, according to a federal grand jury indictment unsealed this week. Now the former officers and 12 others have been arrested and charged with racketeering after a four-year investigation authorities dubbed Operation Prison Cell. The former guards are accused of involvement in a smuggling scheme that undermined the justice system, U.S. Attorney Kenneth Magidson told reporters Wednesday. "Prison is a place where inmates are supposed to do their time," he said, "not where they do their crime."Former prison guards are charged with racketeering for allegedly smuggling cell phonesOfficials say prison inmates used the phones to plot serious crimes, including killingsThe arrests of 17 former corrections officers were part of Operation Prison Cell 
 Question:In the _, authorities said Wednesday that rampant corruption had festered since 2005.

Prison