A ferry connecting an island off the coast of Georgia resumed operations Monday while the investigation to see what might have caused a deadly dock collapse that killed seven people continues.

Georgia authorities said Sunday they are investigating the “catastrophic failure” of a dock gangway that collapsed and killed seven people on an island off the state’s Atlantic seacoast, where crowds gathered for a celebration by the island’s tiny Gullah-Geechee community of Black slave descendants.

A day of celebration ended in tragedy after officials say a “catastrophic failure” led to a dock gateway collapsing on a small Georgia island.