In April 2021, construction workers at an Amazon warehouse site in Connecticut were horrified when they found rope shaped like a noose hanging from the ceiling. The hate symbol was quickly reported to their bosses.

Two days later, five additional nooses appeared. The next month, two more were discovered.

Now, five Black and Hispanic electricians who worked at the construction site in Windsor, Conn., have filed a federal civil rights suit against Amazon and two contractors, Wayne J. Griffin Electric and RC Andersen. The electricians accuse Amazon and the contractors of failing to take the issue seriously and failing to implement measures that could have stopped the harassment.

The workers also allege they faced retaliation and hostility at their workplace after raising concerns about the nooses.

"The appearance of a noose, even one noose, in a workplace sends a clear message of hostility towards the men of color working there: 'You are not welcome here, and you better watch your back,' " said the complaint, which was filed in late September.

Amazon spokesperson Steve Kelly told NPR: "Hate, racism, and discrimination have no place in our society and are not tolerated at any site associated with Amazon, whether under construction or fully operational. Due to the active legal proceedings, we do not have further comment at this time."

Amazon also said it supported local law enforcement during the investigation.

The two contractors did not respond to NPR's request for comment.

The group of electricians worked for Wayne J. Griffin Electric to help build an Amazon distribution facility in Windsor, just north of Hartford. RC Andersen was the construction manager for the building project.

The suit alleges that the companies' response to the first two nooses at the construction site was "non-existent and ineffective." It was not until the eighth noose appeared that Amazon fully shut down the site for the police to investigate, the plaintiffs say. (A lawyer for the electricians says that contrary to reports at the time, the site was only partially shut down after the seventh noose was discovered.)

When the FBI got involved to assist the local police with their investigation, the suit further claims that managers at Griffin Electric and RC Andersen accused the electricians of hanging the nooses themselves.

"They had vocally complained as witnesses to hateful criminal conduct in their workplace and yet they were now being treated as perpetrators," the complaint reads. Steve Fitzgerald, an attorney representing the electricians, told NPR that as a result of the experience, his clients "are all now in need of therapy to deal with PTSD and anxiety."

The Windsor Police Department told NPR that no arrests have been made. The suit says the FBI investigation is still open.

The electricians are seeking an unspecified amount of financial compensation.

According to the complaint, the incidents at Windsor were not the first time Amazon and the two companies received concerns about nooses.

In 2017, Griffin electricians working on a construction project at an Amazon distribution center in Bloomfield, Conn., discovered a noose inside the building. Although multiple workers witnessed the noose, a Griffin manager did not report it to police because there was no photo evidence, the suit said.

RC Andersen was managing the construction project at the time.

A Washington Post investigation found a total of 55 nooses were discovered at construction sites in the U.S. and Canada between 2015 and 2021 — rarely did the incidents lead to arrests.