New York (CNN) A fire inside a New York City subway car — that appears to be intentionally set — killed a 36-year-old train operator and injured more than 15 others early Friday morning, a senior NYPD official told CNN.

Police have a person in custody who is being interviewed by detectives, the official said. The cause of the fire is still under investigation, but the officials said it "appears intentional" to investigators who found a charred shopping cart filled with burnt clothing and other items inside the subway car where they believe the fire started. An exact cause of the fire will be up to FDNY fire marshals to determine.

As part of the investigation, police are looking at surveillance cameras and probing other reports of smaller fires elsewhere to determine if they are related, the official said.

Authorities received a 911 call around 3:15 a.m. as the a train on the city's 1,2 & 3 subway line was pulling into the subway station at West 110th Street and Lenox Avenue in northern Manhattan.

Responding officers and FDNY crews found three men and a woman suffering from smoke inhalation, the NYPD said. Medics responded to the location and transported 13 people to local hospitals.

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