(Friday, July 2, 1915, approximately 11:40 p.m. EDT; during World War I) — A powerful bomb, concealed beneath the telephone switchboard in the Senate reception room of the United States Capitol, exploded here tonight. The blast, which shattered windows and sent a tremor through the great building, caused no loss of life or injury.

The device, said by authorities to have consisted of dynamite rigged with a timing mechanism, had been placed in the room earlier in the evening. The Senate had long adjourned, and the corridors of the Capitol were largely deserted at the hour of the detonation.

In the aftermath of the explosion, a letter signed “R. Pearce” and addressed to The Washington Star came to light. The writer claimed responsibility for the act, declaring it an appeal for peace and a warning against what he described as voices urging the nation toward war. “This explosion,” the letter read, “is an exclamation point in my appeal for peace. I wished to make enough noise to be heard above the voices that clamor for war.”

Investigators tonight are pursuing leads which suggest the bombing may be the work of Eric Muenter, a man of German birth who once served as a professor at Harvard University. Federal authorities have launched a full inquiry.