TUKWILA, Washington on Thursday fined and three companies for their role in the crane collapse that killed four people in Seattle last April, with officials calling it “completely avoidable,” and Seattle Police confirmed they have opened a criminal Investigation.

The Department of labor and industry released the results of its investigation on Thursday. As experts suspected, the crane overturned in a gust of wind, because the workers who dismantled it, prematurely removed the pins securing the mast sections of the crane, contrary to the instructions of the manufacturer.

This practice appears to have been common in the industry, although it has led to fatal collapses before, investigators said.

The collapse occurred on April 27 in the booming technology district of South lake city, where a crane was used in the construction of Google’s office building. Sections of the crane landed on the building and on traffic below, hitting six cars. Two workers on the crane died, as did two people in the cars. Four other people were injured.

“The incident that occurred was completely preventable,” Department Director Joel Sachs said at a news conference. “If the companies in place followed the rules, the crane would not fall.”

Detective Patrick Michaud, a spokesman for Seattle police, said he could offer no details about the criminal case, except to say he is currently leading violent crime detectives. Labor and industry officials said they were cooperating with information requests from the police.

The collapse of the crane has led to criminal charges before. New York prosecutors have filed manslaughter charges in two separate collapses in 2008, one alleging that the forger failed to properly secure the crane and the other alleging that the crane owner irresponsibly hired a reduced-rate repair company to work on it before then. Fallen. Both cases ended in acquittals.

Regulators issued the largest fine, $ 70,000, to Salem, Oregon-based morrow Equipment Co., which supplied the Gly General contractor crane. GLY was fined $ 25,000, and Northwest tower crane service Inc, which provided the crew, was fined $ 12,000.

Morrow was most culpable because he was an expert on site and should have known and ensured manufacturer instructions were followed, regulators said, while other companies were cited for lack of Executive presence, inadequate training or other Violations.

Two other companies that have been investigated are not responsible, officials said.

Herb said the company will “do everything we can to protect our workers and communities.” GLY declined to comment on the criminal case.

Brian Haight, crane program Manager in the Department, said the manufacturer’s instructions say the crane must be dismantled on sections. As the secondary crane attached to the top of the section is removed, workers pull the pins for that section only, leaving the rest of the tower secure. The pins are about 16 inches long and weigh 26 pounds.

At the crew’s pre-task meeting that morning, they did not review the manufacturer’s instructions for removing the crane, Haight said.

On that day, the secondary crane could not function due to strong winds. So the disassembly crew, waiting for the winds to subside, decided to remove the pins up and down the tower crane and loosen the bolts attaching the tower to its concrete base. When a gust of about 50 mph hit, the crane swayed and collapsed.

The early removal of the pin was blamed after a tower crane mast collapsed during a disassembly in Dallas in 2012, killing two workers. Terry McGettigan, a tower crane specialist in Seattle, wrote a paper after the Dallas pressure relief warning of the dangers of taking labels.

After the April collapse, the Department issued a hazard warning that was distributed to the crane industry internationally. She also asked crane companies in Washington to notify them of the Assembly or dismantling of any tower cranes so that the Department could send an auditor to inspect the crane and ensure proper procedures.

The $ 70,000 fine issued to morrow was the maximum allowed under state rules for a single, intentional workplace safety violation, unless the company has a previous history of such actions before, said Anna Soiza, assistant Director of the Department.

David Boeninger, a Seattle attorney who plans to sue on behalf of one victim’s family, said the state’s investigation explained how the collapse occurred, but not why.

“We know procedures have been violated, but how often, and why? He said. “It’s a fairly common practice of cutting corners and it’s a concern.”