Susan Wager, Henry Fonda's ex wife, was doing laundry in her basement up the street when the explosion happened. "a real quaver ran through the ground," she said later. She ran out on the street and saw two young women covered in soot- they had managed to escape the fire that was raging in the ruined building. One of them was completely naked- she had been taking a shower when the explosion happened. Wager took them back to her house and gave them clothes. She went out in the street for a moment, and when she returned, they were gone.

The women were later identified as Catherine Wilkerson and Kathy Boudin, both in their 20's. Both were out on bail for assaulting a police officer in Chicago. And both were known to be members of the Weathermen, or Weather Underground- a radical student political organization.

Three bodies were eventually found in the remains of the townhouse, all Weathermen members.

One of the bodies was Theodore Gold, who had been a leader of the student takeover at Columbia University in 1968. The Students for a Democratic Society (SDS) were major organizers of these protests. The Weathermen were a radical offshoot of the SDS. The name comes from the Bob Dylan song Subterranean Homesick Blues: "You don't need a weatherman to know which way the wind blows..." In a move of political correctness, they later changed the name to the "Weather Underground".

http://www.columbia.edu/acis/history/1968.html

In the wreckage, the police found blasting caps, pipe bombs, 60 sticks of dynamite, and an antitank shell. It soon became clear that this had been a bomb factory- someone had accidentally detonated a device they were working on. It was later revealed that their target was an officer's dance at Fort Dix, N.J.