Mayor Bill de Blasio says a multi-agency investigation is underway following a deadly crane collapse Friday morning at a construction site in Lower Manhattan. NY1's Roger Clark filed the following report.

It was just before 8:30 a.m. Friday when a loud crash stunned the neighborhood.

"It was a massive crane, and it had fallen over," said witness Francesca Corelli. "Cars were crushed, and there was a woman pinned underneath the crane."

The crane toppled onto Worth Street as workers were moving it to a secure position. It fell across two blocks, from Worth to Hudson streets, killing 38-year-old David Wichs of the Upper West Side as he got out of his car. Three others were injured.

"Our hearts go out to the family of the individual who's been lost and to all those that have been injured," said Mayor Bill de Blasio. "We're concerned for everyone who lives and works in the area to make sure they'll be safe."

The crane was at 60 Hudson Street, the old Western Union building, since last week to replace heavy equipment on the roof. The Buildings Department inspected it Thursday morning, approving an extension of its boom to 565 feet.

"It's a capacity of 330 tons, so it's a very, very large crane," said Buildings Commissioner Rick Chandler. "Perfectly fine in terms of the way it was engineered, but obviously, it requires an investigation as to why this happened."

The mayor said the workers had decided to secure the crane because of 20-mph winds, even though it didn't have be secured unless the wind hit 25 mph.

When it collapsed, the crane damaged several building exteriors. Thankfully, workers had cleared the area as it was being lowered and secured. The mayor says this could have been even more tragic otherwise.

"It was something of a miracle there wasn't more impact," de Blasio said. "And thank God the impact on people wasn't worse because this is an area that normally would have had a lot of people."

People who were there say it was a sight and sound they won't forget.

"This has just been a terrible thing that has happened in our neighborhood," Corelli said.

The city says none of the surrounding buildings suffered any structural damage.

The collapse led to street closures and 1 trains bypassing two nearby stations.

The mayor does not expect things to be back to normal here until Monday at the earliest.