Haaretz :
In early April, 2003, an Islamic Jihad activist went to a Western Union office in Lebanon and ordered a money transfer to Hebron. The Justice Department authorized Western Union to release this information to the FBI and the CIA, and eventually to the Shin Bet. According to Suskind, all this took just minutes, enabling Israeli intelligence to track the person who collected the transfer in Hebron and to uncover the terror cell.
According to the book, this method was used successfully many times over the next year and a half, until autumn 2004, when Palestinian operatives realized that their Western Union transfers were being used to trap them.