A mural celebrating African-American achievement was defaced with swastikas on Thursday in Hyde Park, police said. They are investigating the incident as a possible hate crime.

Four swastikas were spray painted over the faces of four Black Panthers featured in the mural in southwest Los Angeles, said LAPD officer Jeff Lee.

Investigators believe it is an isolated incident, Lee said. No arrests have been made.

A dozen artists had painted the two-block long mural, entitled “Our Mighty Contribution,” over two years, wrapping up in 2002, said Gregory Everett, a filmmaker and the curator of the mural. Located on the busy Crenshaw Boulevard, the mural chronicles the historical contributions of black people, Everett said.

Over the past 18 years, only a few people have scribbled their names on the wall, Everett said.

Frederick Douglass, Harriett Tubman and Martin Luther King Jr. are also featured on the mural.

“It’s just absolutely a travesty. It’s devastating. It is upsetting,” Jasmyne Cannick, a strategist and political commentator who alerted the police, said in a video posted on social media. “And we can’t stand for this.”

“The wall is our history,” Cannick said. “It’s a source of pride in our community. It tells our story.”

Enkone Goodlow, a Los Angeles-based artist who painted the portion of the mural with the four Black Panthers, told CNN affiliate KABC he immediately went to touch up the mural when he learned swastikas has been painted across the faces of “some of my beloved Black Panthers.”

“I was hurt because that portion of the mural has never been defaced,” he told CNN in an interview.

Goodlow, 45, said he used a photo of former Panther leader Kathleen Cleaver, which he had torn out from a library book more than 20 years ago, as inspiration for the mural of the four female Black Panthers.

Goodlow told the station he felt terrible about what happened because he believes the Black Panthers were highly misunderstood.

“A lot of people thought that they were a hate group, and that they had a disdain hate for whites,” he said. “The only thing that the Black Panthers had problems with, was hate itself.”

“So someone who has hate in their heart would come and put hate going across their face,” he said.

The Black Panther Party was started by Huey Newton and others in 1966 as urban riots were spreading the country. The beating or killing of blacks by police under suspicious circumstances sparked many of the riots. Newton discovered a loophole in California law that allowed the open carry of loaded weapons, and the Panthers used that loophole to monitor police patrols in black neighborhoods to ensure black people were not mistreated.

Everett said there must have been a reason why the vandal targeted that specific section of the mural.

“Whoever did it felt like that was the biggest threat to their agenda,” he said.