MEMPHIS, Tenn. (AP) — Investigators announced on Wednesday that a fire causing extensive damage to a historic Black church was deliberately set. This church, known as the headquarters for the 1968 sanitation workers’ strike that attracted the Rev. Martin Luther King Jr. to Memphis, played a significant role in history.

The Memphis Fire Department stated that the fire at Clayborn Temple, which was in the midst of a long-term renovation, originated from within the church. Authorities are on the lookout for a person linked to starting this fire.

In the early hours of April 28, flames consumed the downtown church. Later on, Memphis Fire Chief Gina Sweat mentioned that while the building’s interior was completely destroyed, there remains a possibility of preserving some of its exterior.

The fire department said May 14 that the building had been stabilized and investigators would use specialized equipment to study the fire’s cause.

“Clayborn Temple is sacred ground — home to generations of struggle, resilience and creativity,” Anasa Troutman, executive director of Historic Clayborn Temple, said Wednesday. “This act of violence is painful, but it will not break our spirit.”

Located just south of the iconic Beale Street, Clayborn Temple was built in 1892 as the Second Presbyterian Church and originally served an all-white congregation. In 1949 the building was sold to an African Methodist Episcopal congregation and given its current name.

Before the fire it was in the midst of a $25 million restoration project that aims to preserve the architectural and historical integrity of the Romanesque revival church, including the revival of a 3,000-pipe grand organ. The project also seeks to help revitalize the neighborhood with a museum, cultural programing and community outreach.

King was drawn to Memphis in 1968 to support some 1,300 predominantly Black sanitation workers who went on strike to protest inhumane treatment. Two workers had been crushed in a garbage compactor in 1964, but the faulty equipment had not been replaced.

On Feb. 1 of that year, two more men, Echol Cole, 36, and Robert Walker, 30, were crushed in a garbage truck compactor. The two were contract workers, so they did not qualify for worker’s compensation, and had no life insurance.

Workers then went on strike seeking to unionize and fighting for higher pay and safer working conditions. City officials declared the stoppage illegal and arrested scores of strikers and protesters.

Clayborn Temple hosted nightly meetings during the strike, and the movement’s iconic “I AM A MAN” posters were made in its basement. The temple was also a staging point for marches to City Hall, including one on March 28, 1968, that was led by King and turned violent when police and protesters clashed on Beale Street. One person was killed.

When marchers retreated to the temple, police fired tear gas inside and people broke some of the stained-glass windows to escape. King promised to lead a second, peaceful march in Memphis, but he was shot by a sniper while standing on the balcony of the Lorraine Motel on April 4.

After King was assassinated and the strike ended with the workers securing a pay raise, the church’s influence waned. It fell into disrepair and was vacant for years before the renovation effort, which took off in 2017 thanks to a $400,000 grant from the National Park Service.

Clayborn Temple was placed on the National Register of Historic Places in 1979. A memorial to the sanitation workers, named “I AM A MAN Plaza,” opened on church grounds in 2018.

About $8 million had been spent on the renovations before the fire, and the exterior had been fully restored, Troutman said.

She said in a recent interview that two chimneys had to be demolished before investigators from the Bureau of Alcohol, Tobacco, Firearms and Explosives could safely work on the property, but the church organ had been removed before the fire.

As the fire was burning, she said, people went to the “I AM A MAN” memorial and stood at a wall where the names of the striking sanitation workers are listed.

“I watched that wall turn into the Wailing Wall, because people were literally getting out of their cars, walking up to that wall and wailing, staring at the building on fire,” she said.