White House staffers unwittingly found themselves in the middle of a Capitol Police investigation Wednesday afternoon, after the vehicle they were driving set off one of the department’s bomb-sniffing dogs.Capitol Police spokeswoman Sgt. Kimberly Schneider said the staffers had already been to the Capitol several times Wednesday in a different vehicle. But as they pulled up to the Capitol’s Senate-side barrier at about 4:15 p.m., the dogs alerted officers during a routine sweep.Following protocol, officers called in the department’s bomb squad to search the vehicle and closed off the Senate Plaza, along with the surrounding streets. Police officials also sent out an alert to staffers, directing them to avoid the area because of an investigation into “a suspicious vehicle.—Bomb-sniffing dogs are trained to detect explosive material, but they often alert officers when they smell common products that have similar properties to the chemicals they are trained to detect. That was apparently the case with the staffers: By 5 p.m., their vehicle was cleared.