Updated: 4:17 p.m.Hill staffers had a temporary scare Tuesday afternoon as the Capitol Police imposed a lockdown on all buildings in the Capitol complex in response to reports of a man with a gun bound for the Capitol.Around 3:30 p.m., police used intercoms to instruct Hill staffers to stay in their offices with their doors locked. But within 15 minutes, police “cleared the investigation with negative results— and reopened the Capitol complex “for routine business,— according to an e-mail sent to Hill staffers.The police were following up on a report of a man with a gun alleged to be on a Metrobus headed toward the Capitol. After investigating, they found there was no evidence to support the allegation. “The situation is stabilized, there is no need for alarm,— states the e-mail from the Capitol Police.One aide to a House Democrat said that moments after the announcement, she could hear people running down the halls of the Cannon Building, which she assumed to be staffers trying to get inside their offices.“Well, that was terrifying,— the aide said after the matter was resolved.