From Atrios' message board, two stories (the links are to the original postings):

First, from "ck":

Is this why "They hate our freedom"?

I have a freind in the process of immigrating. His wife is American and he's been here for 10 years, first going to school on a student Visa and now he has a work permit. INS called him in to 'register' last month and then threw him in jail and threatened to deport him. If his wife wasn't an American they would have deported him the next day despite the fact that he's spent the last 10 years building a life here-legally. He's, of course, scared out of his mind but fortunately they have the resources to secure a good lawyer to help them, many immigrants do not. I'm thankful that they can read the comments of people here and know they are not alone and that some people here do care about them.

Second, from Nick Sweeney:

For the sake of contrast, my friend Danny has shown the necessary documentation for his application for permanent residency. As he says, he has a big advantage: he's British. Were he from a Middle Eastern country, the INS would most likely not be returning forms with slight errors for resubmission; they'd be having him arrested.

And finally, from zarathustra2101, an insight:

According to the AP "The Iranian protesters said many of those detained were victims of official delays in processing visa and green card requests."

And the OC Register "all are in various stages of obtaining their green cards. Most had received INS letters telling them their applications had been accepted."

We need to get these letters scanned and uploaded where everyone can see them. We need to document every instance of "official delay" - before the evidence "disappears".

Let's be honest here. This has nothing, absolutely NOTHING, to do with the legality or illegality of their immigration status and everything to do with arresting "undesirables" solely due to their country of origin by whatever means are possible. This is like emptying an M-60 into a crowd in order to bring down the one guy who you think might be a drug dealer. It's absolutely unacceptable.