The FBI says a powder mailed to several locations in New York and New Jersey, including at least five hotels near the site of Sunday's Super Bowl, appears not to be dangerous.
The agency says further testing is being conducted on the substance. It says it is "within normal values."
It was also sent to former New York City Mayor Rudolph Giuliani's business in Manhattan.
At the Homewood Suites in East Rutherford, General Manager Thomas Martucci said when he opened up a letter sent to the motel, yellow powder fell out.
He says a typed letter inside referenced al-Qaida and the Dallas FBI.