MIAMI (AP) — Miami authorities are scrutinizing a fire station where a noose was found hanging over a black firefighter's family photo ruined by lewd drawings. City officials fired six firefighters and five others could be suspended or demoted.

Termination letters sent to The Associated Press on Thursday said the fired firefighters drew or helped draw pictures of penises on personal photos of a colleague. One of them was a captain and another one a lieutenant. The captain failed to report the incident and lied to investigators, according to the letters.

The letters don't say who created the noose that was placed over what looked like a family picture, but city manager Daniel Alfonso says the investigation continues.

"City of Miami Fire Rescue is an ethnically and racially diverse department and one of the best in the country," said Alfonso in a statement. "We cannot and will not tolerate behavior that is disrespectful, hurtful and compromises the integrity of the department and the City of Miami."

The fire department's chief, Joseph Zahralban, said the victim was a lieutenant who has worked there for 17 years. He described the Sept. 9 incident as a "hideous, distasteful act of hate." After it was reported, he transferred employees to other stations.

When the police department began an internal investigation, 11 firefighters were suspended without pay for having some involvement. Of the six firefighters who were fired, two were supervisors who lied to investigators, according to the dismissal letters. One of them is a lieutenant accused of encouraging and helping subordinates draw lewd pictures on the photos.

The firefighters have up to 10 days to dispute their termination before Zahralban.

It is the second incident involving a noose and firefighters in South Florida this year. In June, a noose was found hanging over the chair of a black firefighter recruit in a training session in Pompano Beach, leading to one firing and three resignations.

Experts have pointed out an increase in the use of hate symbols such as nooses and swastikas around the country. Nooses have appeared in the past few months in numerous public places, from museums in Washington, to universities in Maryland and Kansas, a high school in Oklahoma and a church in Alabama.