Yan Feng, 39, of Daly City, said he unsuccessfully tried to use his passport to ignite gasoline he had poured on the consulate's door and steps on New Year's Eve, according to an FBI affidavit.
No one was injured in the fire that charred a doorway and damaged the lobby of the building.
Feng, who has permanent resident status, made his first court appearance Monday on charges of causing damage to property of a foreign government and arson.
Johnson said the investigation into the motive is ongoing but the FBI believes that terrorism, politics or civil rights were not involved. "Right now, we're looking at this as purely a criminal matter," he said.
A four-page FBI affidavit filed in support of federal charges said after Feng called Daly City authorities claiming to be the arsonist, officers detained Feng.
In an interview with FBI agents, Feng said he bought the gasoline at a gas station near the consulate. He said he drove to the consulate, then placed two containers filled with gasoline at the consulate's front door. When his passport failed to burn, Feng used a lighter, igniting the gas before driving away, the affidavit said.
On Friday, Feng called Daly City police saying he wanted to surrender. Police and federal agents arrested him at his home.
Neighbor Tony Shiu says he saw about a dozen police cars that afternoon.
"And then I noticed one man had a green windbreaker that said 'Joint Task Force' and I was just wondering," Shiu said.
The couple that owns the house where Feng was arrested did not want their names used. They say Feng rented an in-law unit built on the garage level and he moved there in June with his wife and two children.
They're now separated and live apart.
The landlords said they knew very little about Feng, except that he always paid his rent on time.
FBI agent Michael P. Eldridge said in an affidavit that after being advised of his right to remain silent, Feng told agents "he targeted the Chinese Consulate because all the voices he had been hearing were in Chinese, and the Chinese Consulate had to have been involved." There was no further explanation in the document.
The U.S. attorney's office declined to comment on the case. Feng's attorney, public defender Steven Kalar, could not be reached. Feng returns to court next week.
Consulate workers said surveillance cameras showed a person exit a van with two buckets of gasoline, pour the fuel on the building and ignite the blaze. The FBI said Monday that agents recovered a minivan believed to be the one seen in the video from a residential complex across the street in the city's Western Addition area.
The FBI said no bomb-making materials were found, but they declined to discuss evidence.
Consulate spokesman Wang Chuan has condemned the attack and would not speculate on a motive.
In March 2008, a group of people poured flammable liquid on a security gate at the rear of the building and set it on fire. No injuries were reported.
ABC7 News contributed to this report.