Since his arrest, friends have continued to post entries on his Web log (www.alfarhan.org) on his behalf under a banner that reads “Free Fouad” and features his picture.

“The issue that caused all of this is because I wrote about the political prisoners here in Saudi Arabia, and they think I’m running an online campaign promoting their issue,” the letter continued, saying that Mr. Farhan had been asked to sign a statement of apology.

“I’m not sure if I’m ready to do that,” he wrote. “An apology for what? Apologizing because I said the government is a liar when they accused those guys to be supporting terrorism?”

Ahmad al-Omran, a blogger and a friend of Mr. Farhan, said that Mr. Farhan had been the first Saudi blogger to be detained by state security. The arrest created widespread anxiety among other Saudi bloggers and advocates, he said.

“An incident like this has its effect,” Mr. Omran said by telephone. “It’s intimidating to think you might be arrested for something on your blog. On the other hand, this means that these voices on the blogosphere are being heard. But it’s really sad that a blogger who is writing about important issues out in the open would get arrested, while there are extremists who call for violence and hate, and the government is not doing much.”