Police in San Francisco arrested a man early Sunday morning they believe to be responsible for setting a portable toilet on fire in the Pacific Heights neighborhood, officials said, though it was unclear if he was the person behind a string of portable-toilet arsons that have plagued the city for years.

Albert Sodini, 51, of San Francisco, was taken into custody around midnight on the 2500 block of Clay Street, said Officer Carlos Manfredi, a police spokesman.

The circumstances surrounding Sodini’s arrest were unclear and it was unknown if he was caught in the act, but he was booked on arson of property, arson to a structure, possession of a flammable material with intent to set fire to a structure and malicious possession of a destructive device, all felonies, Manfredi said.

Maria Sodini, Albert’s mother, said police came to her son’s North Beach apartment, which is in the same building as hers, around noon Sunday and carried away a computer and at least two lighters, which she said he used as a smoker and to light the stove.

“He couldn’t have done what they are saying,” she said. “I am very concerned for him.”

Maria Sodini said she spoke with her son soon after police searched his house and that, through tears, he denied having any involvement in the fires.

“He was crying and he told me ‘I did nothing wrong. I don’t know why they arrested me,’” she said.

In February, two portable toilets burned at a construction site in the South of Market nieghborhood, though it was unclear if arson was the cause, KPIX reported. In January, a toilet was torched on Divisadero near Ellis Street, according to local news site Hoodline.

In 2012, at least three portable toilets were burned near Lake Merced and in the Richmond District, with officials suspecting arson in all three blazes.

By far the most active period of bathroom blazes was in the fall and winter of 2008 and 2009, when more than two dozen portable toilets were burned, mostly on Russian Hill and in surrounding neighborhoods.

There were no reported injuries in any of those fires and no suspects were arrested.

Police wouldn’t speculate as to whether they suspected Sodini in any of the previous cases of arson, saying only that the investigation was ongoing and was being spearheaded by the department’s arson task force.

Kale Williams is a San Francisco Chronicle staff writer. E-mail: kwilliams@sfchronicle.com Twitter: @sfkale