When the home of Nikki Joly burned down in 2017, killing five pets, the FBI investigated it as a hate crime.

After all, the transgender man and gay rights activist had received threats after having a banner year in this conservative town.

In the prior six months, he helped open the city’s first gay community center, organized the first gay festival and, after 18 years of failed attempts, helped lead a bruising battle for an ordinance that prohibits discrimination against gays.

For his efforts, a local paper named him the Citizen of the Year.

Authorities later determined the fire was intentionally set, but the person they arrested came as a shock to both supporters and opponents of the gay rights movement. It was the citizen of the year — Nikki Joly.

“It’s embarrassing,” said Travis Trombley, a gay resident who fought for the ordinance. “How do you do it to the community you have put so much effort into helping?”

Why Joly, 54, would allegedly burn down his home remains a mystery. He didn’t own the house, which was insured by its owner, police said.

His attorney said the lack of a motive cast doubt on the case.

Meanwhile, a police investigative report suggests a possible reason for the fire.

Two people who worked with Joly at St. Johns United Church of Christ, where the Jackson Pride Center was located, said he had been frustrated the controversy over gay rights had died down with the passage of the nondiscrimination law, according to the report.

The church officials, Barbara Shelton and Bobby James, when asked by police about a possible motive for the fire, said Joly was disappointed the Jackson Pride Parade and Festival, held five days before the blaze, hadn’t received more attention or protests.