The investigation conducted by the FBI's Office of Professional Responsibility (OPR) began after Grassley wrote a March 19 letter to FBI Director Robert Mueller and Robert Bonner, commissioner of the Bureau of Customs and Border Protection, expressing concern about a potential violation of the First and Fourth Amendments.
A letter from the FBI acknowledged that the FBI was responsible for retaining the package. The letter also stated that officials would provide a briefing on the outcome of the investigation and answer questions about the incident.
"I appreciate that the FBI is taking this seriously and conducting an internal investigation. It's highly unusual for the government to intercept communications of the media, and I want to make sure we don't have any attempts to censor or stymie the news. If so, the FBI should own up, take responsibility, apologize and ensure it does not happen again," Grassley said.
Customs has yet to provide any official response to Grassley's inquiry. "I don't know what the Customs service has to hide. Maybe this is just the tip of the iceberg," Grassley said.
The FBI and Customs have admitted that a package of documents from an Associated Press reporter in the Philippines to another AP reporter in Washington last year was inspected, seized and retained.
The package contained an FBI lab report that can be found in public court records. Reportedly, the report was seized and kept because it was "sensitive," according to one official quoted in a story about the matter. A copy in the possession of Grassley's staff is not labeled as "law enforcement sensitive" or "classified."