Homicide detectives are investigating the fatal fall this morning of a construction worker at the site of the Carlyle Condominiums undergoing conversion at Wood Street and Fourth Avenue, Downtown.

A news release issued by city police this afternoon said it appears Brian Obermeier, 33, of Etna, fell 20 stories from the roof of a building adjacent to the one under construction.

The release said the man was last seen getting off an elevator on the 20th floor of the former Union National Bank, which is being renovated, and heading toward stairs that lead to the roof. Workers regularly use that route or the elevator from the adjacent Commonwealth Building on Fourth Avenue to get to the roof.

The release said it appears the victim fell from the Commonwealth Building.

An investigator from the federal Occupational Safety and Health Administration was at the scene.