NEW YORK - A huge construction crane being lowered to safety in a snow squall plummeted onto a Lower Manhattan street Friday, killing a Wall Street worker and leaving three people hurt by debris, officials said.

The mobile crane's boom landed across an intersection, smashed several car roofs and stretched much of a block after the accident around 8:25 a.m., about 10 blocks north of the World Trade Center.

Nearby buildings were evacuated after the collapse while fire and utility officials checked and rechecked for gas leaks.

The collapse killed David Wichs, a mathematical whiz who worked at a computerized trading firm, his family said. Born in Prague, he had immigrated to the United States as a teenager and graduated from Harvard University, said his sister-in-law, Lisa Guttman.

"He really created a life for himself. He literally took every opportunity he could find," she said through tears.

Dawn Kojima, of Nutley, was among the three other people injured. According to witnesses, Kojima heard the screeching of the crane beginning to collapse and pressed herself against a building to get out of the way.

Kojima was struck by some debris and was taken to a Manhattan hospital after being helped by a New York City police officer. She is expected to recover.

A bystander video taken through a window high above the ground showed the arm descending, then taking the entire crane to the ground.

The accident happened as workers were trying to secure the crane against winds around 20 mph by lowering the boom, which had been extended to as long as 565 feet the day before, officials said. Because the crane was being lowered, workers were directing pedestrians away from it on a street that otherwise would likely have been teeming with people.

Officials were working to determine why the crane fell. An employee who answered the phone at the offices of crane owner Bay Crane would say only that an investigation was underway and wouldn't give his name. The company officials identified as the crane operator, Galasso Trucking Inc., didn't immediately respond to messages about the collapse.

The Associated Press wire services contributed to this report.