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: Jack Warner been forced to hand over his passport after police officials deemed him a flight risk. Warner was photographed outside Trinidad's Arouca police station on Thursday, where he has to report twice a week to under his bail agreement. On Wednesday, Trinidad Attorney General Garvin Nicholas said that officials feared that the former FIFA Vice President would flee the island after facing U.S. federal corruption charges, with the following day's measures ensuring that possibility is now not an option. 'Any person with the level of resources that Mr Warner has would be considered a flight risk,' Nicholas said. 'We certainly made it a lot more difficult for him to escape or leave the country.'Jack Warner spotted outside Trinidad's Arouca police station on Thursday72-year-old has to report there twice a week under bail agreementWarner is facing U.S. federal corruption charges for his time at FIFAWalter De Gregorio has resigned as FIFA's director of communicationsHe made a joke live on Swiss TV regarding the arrests of FIFA officials 
 Question:Valcke said: '_ has worked incredibly hard for the past four years and we are immensely grateful for all he has done.
Output:
Walter De Gregorio