Broadway in downtown Denver shut down for more than an hour during morning rush, but nobody knows why

Slow traffic on Broadway isn't unusual on weekday mornings, but Thursday was particularly frustrating for drivers as they approached the state Capitol. Despite a sign warning of only an approaching left lane closure, it turns out the entire street was closed between Colfax and 14th Street. 

Broadway was closed from approximately 7:30 a.m. to  8:30 a.m.  Denver police officers routed drivers east and west on Colfax to get around the closure.

CBS News Colorado asked the Denver Police Department why Broadway was closed, but the media relations unit told us they had no calls for service and that perhaps the closure was due to an event. CBS News Colorado checked with the Civic Center Conservancy, but they were unaware of any events on Thursday morning. 

DOTI, which is Denver's Department of Traffic and Infrastructure, has not yet responded to requests for information. Neither has RTD, which operates the Civic Center Station a block-and-a-half away.

Colorado State Patrol has jurisdiction over the state Capitol, but they also had no knowledge of the closure.

CBS News Colorado will continue to seek answers, but it's looking like this closure may remain a mystery.