LONDON — He is known as a homeless hero.

But the role of a man who comforted victims and helped the wounded in the deadly terrorist attack in Manchester, England, this spring was thrown into question on Wednesday as he appeared in court, charged with stealing from the people he had aided. He pleaded not guilty.

After a man detonated a bomb as fans were leaving a pop concert at Manchester Arena in May, Chris Parker and Stephen Jones, two homeless men who happened to be nearby, decided to help. Mr. Parker comforted a girl who had lost her legs and cradled a dying woman in his arms.

“It knocked me to the floor,” Mr. Parker, who had been begging in the arena’s foyer, said of the blast at the time. “And then I got up, and instead of running away, my gut instinct was to run back and try and help.”