Several homes were raided by the FBI in Portland, Oregon earlier this week. And subpoenas seeking testimony before a federal grand jury were reportedly handed out in Seattle and Olympia, Washington as well.
Occupy Wall Street and other activist groups are urging resistance to the federal probe.
Occupy's resurrected an old poster that first received notoriety when CAIR posted it in California about a year and a half ago. It carries a direct message: "Don't talk to the FBI."
Meanwhile, Seattle police reportedly carried out a raid earlier this month on an apartment where members of Occupy lived. That raid was also reported as being tied to investigation of May Day activities.