With all Seattle engaged in a monumental stand-off over the future of global capitalism, the agents said they had discovered an overnight break- in at one door and found other internal doors taped open. Yesterday's sessions were delayed by five and a half hours - an inconvenience rather than a real threat, but one that suggested the whole meeting might just be ground to a halt as the demonstrations escalate through the week-long meeting.
The incident set the tone for the day, as thousands of environmentalists and steelworkers jammed the streets around the centre in a series of demonstration against the impact of WTO free-trade policies on labour and the environment.
"WTO - Just Say No," the crowd chanted amid a sea of cardboard turtle outfits, dragon banners and various placards of cows and birds emblazoned with the words "We are Not a Trade Barrier".
Despite fears of clashes with police, the atmosphere was mostly peaceful and upbeat, with just two tense moments as members of the "Vegan Resistance" unfurled a banner from the roof of a city bus and other activists shook the glass panelling of a Nike Town store. Riot police formed phalanxes and marched menacingly through adjacent streets, but there were no arrests.
Among the protesters was Jose Bove, the farmer famous for pulling the roof off a McDonald's in France, who offered his support to the "good American people" for opposing genetically modified foods and hormones in beef in a rally at an intersection outside a downtown McDonald's.
Earlier in the day, five environmentalist stuntmen hoisted an anti-WTO banner atop a crane overlooking Seattle's main freeway, the second such stunt in three days.
Activists also took over an abandoned block of flats, vowing to house up to 300 protesters and call attention to poverty and homelessness.
The protests will reach fever pitch this morning with a massive demonstration expected to attract some 50,000 people. More radical groups have vowed to lie down in the streets and spring other civil disobedience surprises in protest at what they see as the triumph of corporate profits over individual and global well-being.
Anti-WTO feeling runs the gamut from red-haired punks with pierced lips, to Midwestern farm unionists and even Christian conservatives like presidential hopeful Pat Buchanan, who arrived for a series of meetings.
The streets were filled with acoustic guitar music and lusty singing of such folk classics as Woody Guthrie's "This Land is Our Land".