The teen charged last week with arson in connection with the fire on Franklin Street now faces additional charges in connection with the incident.

The 15-year-old boy now faces five counts of burning or destroying personal property in addition to the original charges — two counts of arson of occupied dwellings and one count of arson of an unoccupied dwelling. The new charges address the damage or destruction of four private vehicles and one fire truck during the fire.

Heat damage to the fire truck, a 2008 model, caused several emergency light lenses, the hose cover and some hose to melt, said Debbie George, spokeswoman for the city. The cost of repairs is not yet known, she added.

The fire, which destroyed an occupied house, a duplex and an unoccupied home, along with a two-story garage, started in the vacant house and quickly spread to the buildings on either side.

A total of 11 people were displaced from their homes by the blaze, and four firefighters were taken to the hospital with minor injuries suffered while fighting the fire.

City officials have declined to release details about how the fire may have started.

The vacant house at 120 Franklin St. had been the subject of neighbors’ complaints for some time, and it had come to the attention of Suffolk’s codes enforcement office 14 months ago, when the city first issued citations for code violations to its owner, Thomas W. Dana III.

Dana has been cited for violations on properties he owns at least three times, including at least two times for the house that was lost in the fire.

According to General District Court records, he had failed to scrape and paint the house; secure it against unlawful entry; and repair the front porch, broken windows, exterior walls, interior walls, an overhang extension, trim and other aspects of the structure.

A judgment was entered against him in November, and he was fined. As of last week, he had not paid the fines.