WASHINGTON (AP) âÄî Details emerged Thursday behind the break-in of Republican vice presidential candidate Sarah Palin’s e-mail account, including a first-hand account suggesting it was vulnerable because a hacker was able to impersonate her online to obtain her password. The hacker guessed that Alaska’s governor had met her husband in high school, and knew Palin’s date of birth and home Zip code. Using those details, the hacker tricked Yahoo Inc.’s service into assigning a new password, “popcorn,” for Palin’s e-mail account, according to a chronology of the crime published on the Web site where the hacking was first revealed. The FBI and Secret Service launched a formal investigation Wednesday. Yahoo declined to comment Thursday on details of the investigation, citing Palin’s privacy and the sensitivity of such investigations. The person who claimed responsibility for the break-in did not respond Thursday to an e-mail inquiry from The Associated Press. “i am the lurker who did it, and i would like to tell the story,” the person wrote in the account, which circulated on the Internet. What started as a prank was cut short because of panic over the possibility the FBI might investigate, the hacker wrote.