Website mapping DC’s tunnel network warned FBI of suspicious traffic ahead of Capitol riot

The obscure online resource saw a spike in activity from dubious forums and message boards.

The Washington Post via Getty Images

The FBI received a tip off about suspicious activity ahead of the Capitol Riot on January 6th from a surprising source. Elliot Carter, a recreational mapmaker, contacted law enforcement after his site about Washington, D.C.'s underground infrastructure witnessed a spike in activity from suspicious websites. His warning eventually made it to the highest ranks of the Capitol Police, according to a new investigation by News4 I.

Normally a mecca for local history buffs, the Washington Tunnels website Carter oversees was flooded with nationwide visitors in the days before the insurrection. A deeper review of the traffic analytics revealed that many of the clicks were coming from hyperlinks shared on anonymous message boards, sites and forums named after militias or firearms, or using Donald Trump’s name. Though the initial interest originated from the deepest and darkest recesses of the web, it eventually transitioned onto popular social media sites, including Twitter.

The Washington Tunnels website itself was a labor of love. Back in 2018, Carter set to work building his online resource of the District's subway and freight rail tunnels, pedestrian passageways, underground steam tunnels and sewage and water pipelines. But, even then he was rebuffed by some government agencies concerned by the security and terrorism risks that could arise from publishing such information online.

Carter's "online tip" to the FBI was mentioned in the US Senate Rules and Homeland Security committees' June 2021 review of the US Capitol insurrection. In a statement to News 4 I, the US Capitol Police said its leadership had been alerted "to the spike in website traffic regarding maps" ahead of the insurrection. But, added that its wider intelligence gathering "didn't reveal [that the expected] large-scale demonstration would become a large-scale attack on the Capitol Building."