David Kernell allegedly broke into a school server about eight years ago while studying at in Harker Heights, Texas, one of his former teachers said Wednesday.

Kernell, 20, was charged Wednesday with one felony count of accessing a protected computer for allegedly breaking into the private Yahoo e-mail account of Palin, the Republican vice-presidential candidate. Some of Palin's private e-mail was eventually on the Wikileaks Web site last month.

In a description of the attack, an anonymous hacker named "rubico," suspected to be Kernell, said he got into the account by guessing the high school where Palin met her husband and tricking Yahoo's password reset system into letting him into the account.

According to Kernell's former history teacher, Tracey McDaniels, this isn't the first time the student has been accused of using clever guesswork to get into a computer.

The other incident allegedly occurred around 2000, when Kernell was in the seventh grade. Kernell and an accomplice guessed the password to a server used to store teaching materials at the school and were able to log on to the system, McDaniels said.