The only appropriate response to a claim of nooses in the workplace is an immediate investigation. That may require involving the police.
Show you take the incident seriously even if the source may be a customer or a contractor. It’s the right approach and the one most likely to cut any potential liability after the fact.
Recent case: James and Mark, who are black, worked for the city of York at a water treatment facility. Some of the facility’s functions were contracted out to an outside company, including the shower area. The men complained that someone had allegedly dirtied the shower area.
The next day, they returned to the shower area and discovered what they thought was a noose made of rope. They again complained. A few days later, they found a similar rope hung at another building. Again, they complained. Police were called in. However, no one could determine who had hung the ropes or whether they were intended to look like nooses.
The men sued their employer and the contractor, alleging a hostile work environment.
They lost against the contractor because they didn’t work for it. They also lost their case against the city of York because it had done everything it should have done when confronted with the noose claims—it had launched an investigation, called in police and tried to figure out who was responsible. (Hollinghead, et al., v. City of York, et al., No. 14-2068, 3rd Cir., 2015)