A man linked to white supremacist movements pleaded guilty on Monday to setting a fire that destroyed an office at a historic social justice center in Tennessee with ties to champions of the US civil rights movements, a court document shows.

Regan Prater also pleaded guilty to attempting to aid a foreign terrorist organization for efforts to provide the militant group Hezbollah “a list of personally identifiable information for individuals purportedly affiliated with the government of Israel”, according to a criminal information filed in February.

Sentencing is scheduled for 9 September in Knoxville.

A public defender representing Prater did not immediately respond to an email and phone message requesting comment.

Prater was arrested in April 2025 in connection with the arson at the Highlander Research and Education Center in New Market. The arrest came more than six years after the March 2019 blaze, which caused more than $1.2m in damage, prosecutors say.

An affidavit filed in federal court in east Tennessee said Prater’s posts in several group chats affiliated with white supremacist organizations connected him to the crime. In one private message, a witness who sent screenshots to the FBI asked a person authorities believe was Prater whether he set the fire.

“I’m not admitting anything,” the person using the screen name “Rooster” wrote. But he later went on to describe exactly how the fire was set with “a sparkler bomb and some Napalm”.

A white-power symbol was spray-painted on the pavement near the site of the fire. The affidavit describes it as a “triple cross” and says it was also found on one of the firearms used by a shooter who killed 51 people at mosques in Christchurch, New Zealand, on 15 March 2019, about two weeks before the Highlander fire.

Prater was initially charged with one count of arson. On Monday, the previous indictment was dismissed in favor of the criminal information – filed in February – which included the charge related to the Lebanese group Hezbollah.

In a plea agreement filed the following day in February, the government agreed that a sentence of no more than 20 years was appropriate.

Prater was previously sentenced to five years in federal prison for setting a fire in June 2019 at an adult video and novelty store in east Tennessee. He pleaded guilty and was ordered to pay $106,000 in restitution in that case.

At the scene of that fire, investigators found a cellphone they later determined belonged to Prater. The phone included a short video showing a person inside the store lighting an accelerant, according to the affidavit.

Highlander is known as a place where civil rights figures including Rosa Parks and John Lewis received training. Parks attended a workshop there on integration in 1955, about six months before she famously refused to move to the back of a bus in Montgomery, Alabama. She always credited Highlander with helping her become a more determined activist.

Parks returned to Highlander two years later with the Rev Martin Luther King Jr for the school’s 25th anniversary celebration. On that occasion, King gave a keynote address on achieving freedom and equality through nonviolence.

The blaze at Highlander broke out in the early morning of 29 March 2019. No one was injured, but decades’ worth of irreplaceable documents were lost. They included artifacts, speeches and other materials from different eras, including from the US civil rights movement.