Kevin "Kayvon" Edson, 25, has bipolar disorder, his mother, Joie Edson said.
He is scheduled to be arraigned Wednesday in Boston Municipal Court on charges of threatening battery, possession of a hoax explosive device, threats to commit a crime, disturbing the peace, disturbing a public assembly and disorderly conduct. It was not immediately clear who his lawyer is.
Edson was stopped late Tuesday after passers-by told an officer they saw him acting suspiciously, including walking barefoot down the middle of a street, veiled in black, in pouring rain, police Superintendent Randall Halstead said.
The man was yelling and screaming, authorities said. Officers removed the veil and a hat and saw that the man's face was painted blue and yellow, investigators said.
The man said he had a rice cooker in the backpack, which was later destroyed. Police determined that the bag's contents were not explosive.
A second suspicious backpack also was found. Officers determined it had been left behind by a media outlet and was not dangerous, but it too was destroyed.
The arrest happened hours after ceremonies to mark last year's Boston Marathon bombings, in which two pressure cooker bombs hidden in backpacks exploded, killing three people near the finish line and injuring more than 260 others.
The backpacks rattled nerves days ahead of this year's marathon. Police kept people away from the finish line area for about three hours Tuesday and trains bypassed the nearby Copley Square station.
"With the marathon coming, our officers are taking it seriously," Halstead said. "The safety of the public is utmost."
Joie Edson declined further comment on her son but said she planned to issue a statement later Wednesday.