QUINCY – Quincy K9 officer Dan Parisi was on patrol Tuesday afternoon when he heard reports come over the radio of a house fire on Norfolk Street with several people trapped inside.

Brewster Ambulance paramedics Hugh Devlin and Rick Weitsen – both off-duty firefighters in other communities – heard the calls too, and happened to be right down the street.

Parisi, Devlin and Weitsen pulled up at 107-109 Norfolk St. at the same time and found flames engulfing the roof and exterior of the two-family home. They rushed in to the first floor, where they found an elderly man, a woman and a young boy. A fourth person had already gotten out of the home.

“You go into firefighter mentality, and just focus on going in and getting them out,” said Weitsen, a Natick firefighter.

Devlin, a Cambridge firefighter, said the residents seemed unaware that the house was on fire until he, Parisi and Weitsen ran in to get them. Devlin and Weitsen carried the elderly man out, and Parisi led the woman and child to safety. They then checked with second floor, which was unoccupied at the time.

Fire officials are investigating the cause of the blaze, which broke out just after 1 p.m. No one was injured in the blaze.

Deputy Chief Jack Cadegan said he declared a second alarm before getting to the scene due to reports that several residents wee trapped inside. Firefighters did a second sweep of the building and confirmed everyone had gotten out by the time they arrived.

“This is a perfect example of a team effort between Brewster Ambulance and Quincy Police were quick on the scene to help evacuate people and Quincy Fire shortly after that,” Deputy Chief Jack Cadegan said. “It was a great job. (Firefighters) knocked it down quick and held the extension to the front part of the building with not too much damage up into the second floor and the attic.”

Parisi said it felt good to help, but that he and the paramedics were simply doing their jobs.

Fire Chief Joseph Barron said a firefighter who is fluent in several Asian dialects spoke with the residents of the home, and the fire prevention office is investigating the cause of the fire. He said the department also notified the Red Cross to assist the residents with temporary housing if necessary.

Jessica Trufant may be reached at jtrufant@ledger.com.