The video, captured by a camera on the front of an eastbound SEPTA Route 31 bus, shows the June 5th collapse that killed 6 people and injured more than a dozen others.
The video shows the scene as the bus approaches the building.
The bus had just left the 23rd and Market stop when the 4-story building collapses onto the Salvation Army thrift store.
A plume of smoke, dust and debris billows onto Market Street. People scramble for cover. The force of the collapse sends one person to the ground. Bus passengers appear stunned.
"It's devastating to see something like that," said attorney Andrew Stern. "It's an important piece of evidence. What it tells us, and we will have a closer look with our experts, you can see is that wall was not properly supported."
Stern represents Maria Plekam, the 61-year-old woman who was trapped in the rubble for more than 12 hours.
She's had both legs amputated and continues to fight for her life at the Hospital of the University of Pennsylvania.
Stern was at the hospital when the video first aired Thursday evening. He says he turned off the television to prevent additional trauma.
"She is not able to talk, but she is able to understand," said Stern. "She did understand a lot while I was talking to her. And I'm just glad I was able to prevent her from seeing the video."
Philadelphia City Council held hearings about the collapse earlier Thursday.
Council members wanted officials with L&I and the fire department to testify, but those officials declined due to the ongoing criminal investigation.
Six people died and 14 others were injured in the tragedy.
The excavator operator, Sean Benschop, is charged with a half dozen counts of involuntary manslaughter.
A long list of civil suits are also forthcoming.
"This is clearly going to help us in the theories that we have which is this involved a number of people from the top not the bottom that caused this problem," Stern said.
Stern told Action News Plekam is scheduled to have another surgery on Friday.