Updated: 1:13 p.m.

Capitol Police responded to a “suspicious envelope” in Sen. John McCain’s (R-Ariz.) office Monday, after staffers alerted the department to the package at about noon.

By 1 p.m., officers had “cleared” the package and found nothing hazardous, police spokeswoman Sgt. Kimberly Schneider said. But she said she didn’t know what about the envelope struck staffers as suspicious.

“It’s an envelope. I’m not sure how it arrived there,” she said, adding that the department has not evacuated the area.

Capitol Police sent out an alert to Senate staffers shortly after noon, asking them to avoid the area around Room 253 “until further notice.” The Capitol Police bomb squad responds to suspicious packages fairly regularly, and most turn out to be innocuous.