At a news conference on Sunday announcing the arrest, city officials said investigators had gone door to door at nearby apartments to seek witnesses, and had reviewed hundreds of hours of surveillance video.

The fire started in a sukkah, a temporary structure erected outside the synagogue each year for the Sukkot celebration, and the flames quickly spread to the synagogue, officials said. Police officers and firefighters arrived within a few minutes of the first 911 call, they said, but by then the blaze was already spreading through the wood-frame building.

“Your loss is our loss, your pain is our pain,” Chief Mike Tusken of the Duluth police said at the news conference in remarks addressed to the congregation. “We grieve with you, we pray with you and we have hope for healing in the days to come.”

The fire followed a wave of anti-Semitic crimes — including the killing of 11 people last year at a Pittsburgh synagogue — that the Anti-Defamation League said had reached alarmingly high levels. The federal Bureau of Alcohol, Tobacco, Firearms and Explosives helped in the Duluth investigation, a standard practice for fires at religious sites. Shawn Krizaj, the city’s fire chief , said that no signs of accelerants were found at the scene.

Houses of worship of many faiths have been the scenes of crimes in recent years. A mosque in Bloomington, Minn., was bombed in 2017. A white supremacist murdered nine people at an African-American church in Charleston, S.C., in 2015. Six people were killed at a Sikh temple in Wisconsin in 2012.

“We understand that our Jewish community feels uneasy in this current political and social environment,” Steve Hunegs , the executive director of the Jewish Community Relations Council of Minnesota and the Dakotas, said in a statement on Sunday. “The image of a house of worship ablaze is a searing reminder of the challenges we face with rising anti-Semitism and bigotry in this country.”

Minnesota politicians from both parties, including Senator Amy Klobuchar, Representative Pete Stauber and Gov. Tim Walz, sent messages of support on social media after the fire.