A group of hackers that hit the Church of Scientology Web site earlier this year have apparently cracked the Yahoo Mail account belonging to Sarah Palin, the Republican nominee for US vice president, according to documents and screenshots posted on the Web.

A security expert called the practice of using private e-mail accounts "incredibly dangerous" for public officials such as Palin.

The group, which calls itself "Anonymous," announced that it had gained access to Palin's Yahoo account in a message last night to, a site that regularly posts confidential documents. Among the files that WikiLeaks had posted for download were five screenshots from gov.palin@yahoo.com, an address book and two digital photos of Palin's family.

One of the account's screenshots shows a short exchange in July between Palin and Sean Parnell, who is running against Democrat Ethan Berkowitz for Alaska's lone congressional seat. In her reply, Palin called Alaskan conservative radio host Dan Fagan "inconsistent and purposefully misleading" in his comments about Parnell.

Another screenshot displays the text of a message to Palin from Amy McCorkell, whom Palin appointed to the Governor's Advisory Board on Alcoholism and Drug Abuse in October 2007. According to a press release issued by Palin's office at the time, McCorkell was previously a private legal investigator, an office worker and a fitness instructor and, like Palin, lives in Wasilla, Alaska.

In the message dated Sunday, McCorkell said: "I am reading the paper and have thoughts and prayers going your way ... don't let the negative press wear you down! Pray for me as well. I need strength to 1. keep employment, 2. not have to choose. Lately I just pray may God's will be done."

The day before, The New York Times had published a story critical of Palin's hiring practices as governor. The story did not mention McCorkell but said that Palin had appointed at least five former high school classmates to state positions since she took office.

Palin has come under criticism for using private e-mail accounts to conduct state business, with some alleging that she and others in her administration have used them to skirt message-retention and public records laws. The Bush administration has been accused of doing the same thing.

"Using private accounts for government or business use is incredibly dangerous," said Adam O'Donnell, director of emerging technologies at message security vendor Cloudmark. "There's a reason why you have an official account. It's so that you can apply proper security management to the account."

Earlier this year, the Anonymous group launched several attacks against the Web site of the Church of Scientology, claiming that it wanted to "save people from Scientology by reversing the brainwashing."

The Republican National Committee and the McCain-Palin campaign had no immediate comment.