Year.

Now to kelsie morgan... with new information this morning on that deadly crane collapse in seattle.

Investigators are working hard to figure out the exact cause of the tragic accident which killed four people saturday.

That investigation likely will not be over for about six months.

But this morning we're hearing from a crane expert..

Who says he feels human error is to blame.

The workers were disassembling the crane when it collapsed... and experts say they did not follow the maufacturer's instructions to dismantle it in sections... taking it apart segment by segment while the top section is secured to another crane.

Instead, it appears all of the pins in this crane..

Which secure each section to the next... had removed in advance... instead of one section at a time.

Experts say that is likely why the crane toppled in what are relatively normal winds for seattle.

The city of seattle has 59 cranes in it... that's the most of any city in the u-s.

L & i investigators found this crane was certified when it was built at this site back in june... and no issues were found.

In studio, i'm kelsie morgan kxly four news.