POMPANO BEACH, Fla. -- A Florida fire chief fired a firefighter recruit and accepted the resignations of three others following an investigation into a noose left hanging over the chair of the only black recruit in a class of six on their last day of training.

The men described what happened on June 7 as a "joke," but Pompano Beach Chief John Jurgle said he won't "tolerate this kind of thing."

Jurgle tells the SunSentinel he found out July 26 and the investigation wrapped up Wednesday. Pompano Beach is north of Miami in South Florida.

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On the day it happened, Vilbert Green left the room to do a cleanup task. When he returned he found the noose dangling over his chair and a table, next to a paper nametag with Green's name on it, Jurgle said. He said Green took a picture.

Pompano Beach firefighter recruit fired, others resign in noose investigation https://t.co/g6xpjwyL7t pic.twitter.com/exwkQHgCpk — Sun Sentinel (@SunSentinel) August 10, 2017

"He was not happy with what was done, but after taking the picture, he decided he didn't want to do anything with it,"Jurgle said. Later, Green showed the pictured to another firefighter outside the class.

That firefighter, according to the investigation, was offended and tried to address it with the recruits.

"They told him they knew nothing of it," Jurgle said. Their denial led the firefighter to report what happened to the captain in charge of training, who took the matter to Jurgle.

Matthew Reilly was fired and recruits Kerop Berberian, Geandy Perez and Austin Sovay resigned.

The chief said he determined during the investigation that Perez tied the knot, but no one ever owned up to putting the noose over Green's chair.

Jurgle said the fact that none of the four men was willing to tell the truth troubled him. He said he learned the four were a tight-knit group, who said they didn't intend any offense.

"I heard the word 'joke' a lot and I said, 'Explain the joke to me, explain how this is funny,' "Jurgle said. "They haven't been able to do that."

"It wasn't a noose. It was a fishing knot," Sovay told the newspaper.

His former colleague Berberian said, "people were let go for the wrong reasons."

The chief said he doesn't want his department associated with that kind of behavior.

"This is not our culture," he said.

The race of the recruits wasn't immediately known. They would have become full-fledged firefighters next year after completing two months of training.