? Construction is on hold at a Yonkers building after a concrete slab plunged six stories and killed a worker Monday.

Investigators say the slab fell as the 40-year-old man, who is believed to be from Pennsylvania, was adjusting it with a crane around 9:15 a.m. The slab, which measures about 28 feet long and weighs several tons, fell from the sixth floor, taking the worker with it. Firefighters and police evacuated the structure. The victim, who was found on the third floor among rubble, was rushed to the hospital with severe head injuries.

Fire officials say they are unsure whether the slab itself or the drop killed the worker. However, they have ruled out operator error or crane malfunction as the cause of the accident. The building, located at 66 Main St., was the scene of another serious accident when a retaining wall collapsed last year.

The victim's name has not been released, but authorities say his family has been notified.

To view the press conference on the accident, go to channel 612 on your iO digital cable box and click on iO Extra.