On September 16, 1920, an unidentified assailant detonated 100 pounds of dynamite packed with heavy iron weights on Wall Street. The explosion devastated the financial district, killing 38 people and injuring hundreds. Investigators from the Bureau of Investigation and the NYPD immediately focused on the primary piece of physical evidence: the horse and wagon used to deliver the bomb.
The horse was destroyed in the blast, but its shoes were recovered, along with broken axles and wheels. Detective William J. Burns directed a massive effort to trace the wagon's origin.
Agents scoured thousands of blacksmith shops across New York, New Jersey, and Connecticut, trying to match the specific, hand-forged horseshoe worn by the horse. Despite interviewing over 4,000 blacksmiths and examining thousands of sales logs, investigators encountered an insurmountable roadblock: horse-drawn wagons were ubiquitous, unindexed, and often sold cash-in-hand without paper records. Furthermore, blacksmiths routinely modified shoes on the spot, erasing unique identifying markers.
The lack of standardized registration for utility vehicles in 1920 meant that tracking a generic wagon was like searching for a needle in a haystack. By late 1921, the trail had gone entirely cold. The failure to track the wagon left the worst terrorist attack on U.
S. soil at the time completely unsolved, cementing it as one of America's most enduring historical mysteries.