The inquiry into the collapse of a mall in Elliot Lake, Ont., has been told that police heard tapping in the rubble about 20 hours after the roof caved in.
However, rescuers were unable to get to the source of the sound because of the debris and precarious state of the building.
While the tapping stopped, police later detected breathing through a special machine.
However, the device might have been picking up sound from other rescuers.
Toronto police Staff Insp. Bill Neadles, in charge of the rescue operation, admitted to lapses in communications as various plans to get to the area were devised.
He also talked about disagreements about releasing information about victims to the media.
Neadles has yet to react to comments from a crane company owner that the urban search team he commanded was essentially clueless and useless.
At times, Neadles as site commander appeared to operate in a vacuum.
For example, he announced a plan to remove a steel beam and concrete slab without speaking to his engineer or operations manager.
On another occasion, Neadles reported a crane would be deployed but the person in charge of operations did not know about it.
“It’s really quite astounding that your operations’ chief didn’t know there were going to be crane operations,” commission lawyer Mark Wallace said.
Neadles admitted it was a failure of communication.
He was also frequently unable to recall who gave him various pieces of information.
Two women died in the collapse of the rooftop garage on June 23, 2012.