WINDSOR, Conn. (WTNH) — Investigators identified persons of interest in connection with nooses found at an Amazon construction site in Windsor earlier this year but say they were unable to establish probable cause to arrest anyone in the case.

The first noose was initially found on Saturday, April 24, but was reported on Tuesday, April 27, police said.

After months of investigating with the FBI and the Connecticut State Police, Windsor Police identified persons of interest who submitted to polygraph examinations. Those persons of interest then decided to stop cooperating with investigators, police said.

Investigators said they found photos of the rafters of the building that were taken on April 22, two days before the first noose was found, but o other relevant information or leads were discovered.

Investigators said they do not have probable cause to arrest anyone allegedly involved, but the case remains open.

“The Windsor Police Department will keep this case open should any new information be developed that would allow for the prosecution of this case within its statute of limitations,” police said in a statement.

A total of eight ropes tied like nooses were discovered at the site over the course of a few months.