“We thought she left our area, but evidently not,” he said.

Dave Sinclair, who works for an airport bus service, said he saw her on Madison Avenue. “She’s like this short,” he said, holding his hand about five feet off the ground. “She had a little shopping cart, black jacket, brown pants and brown hat. She was walking up this way. All of a sudden, all the cans were on fire.”

Chief Rosenbaum said three engines and two trucks responded to the small fires, which left melted, twisted plastic barrels that Grand Central Partnership workers hurried to replace.

The suspect may have set similar fires in the area two weeks ago, the chief said.