Exclusive video shows blast that destroyed New York City buildings - as it happened

NEW YORK -- Video obtained exclusively by CBS New York shows the deadly blast that demolished two buildings in New York City's East Harlem this week - as it happened.

The video shows windows shattering, seemingly out of nowhere, and debris beginning to rain down onto the sidewalk, reports CBS New York's Kathryn Brown. A cloud of thick, black smoke begins to envelop everything as the buildings explode.

A man walking across the street is nearly knocked off his feet by the blast. He ducks, tries to cover his head, and is pushed back, apparently disoriented.

The blast on Wednesday, believed to have been triggered by a gas leak, killed eight people and left more than 60 others injured.

The video was shot by a security camera mounted on a building across the street from now the destroyed buildings at Park Avenue.

"I thought it was an earthquake," said one man Ibrahim Occasion. "It was an explosion, like, connected to your building, so it's insane stuff."

Another witness, Mac Mayor, said, "I looked up -- the building was gone."

As investigators search for what caused the explosion, videos like this one might provide clues. Investigators from the National Transportation Safety Board are piecing together a timeline of the blast.