SAN FRANCISCO (KGO) -- The first in what is expected to be a series of hearings began Thursday at city hall over the sinking of the Millennium Tower in San Francisco's South of Market neighborhood. One supervisor is asking who knew about it, when and what can now be done.
Watch the video player above for Carolyn Tyler's full report.
Click here for a look at more stories and videos about the Millennium Tower in San Francisco.
Click here to read the subpoena formally filed by San Francisco City Attorney Dennis Herrera.