"The house was fully engulfed. You couldn't get inside," Capt. Vincent Tamburro said.
Several officers finally subdued the unidentified 26-year-old man, who was taken to Hackensack University Medical Center with burns and smoke inhalation, Tamburro said.
The officer who was assaulted had to be treated for back and knee injuries and will likely have to miss work for an extended period, the captain said.
The second man -- also 26 and who, like the other man, was temporarily staying with the family -- was charged with interfering with police, a disorderly persons offense, Tamburro said.
The men were trying to get back inside the burning house to retrieve the dog who died, he said.
Social media was filled with comments from pet owners who couldn't understand why the man couldn't be allowed into a burning building.
Others tried to talk sense to them.
"I have a dog I love dearly myself and completely get being distraught and devastated," one wrote. "But I was a witness to all of this. You have no idea what the police went through to work to protect everyone prior to having to detain this poor man and the other gentleman too.
"Was he devastated and distraught? Absolutely! But was he a danger to himself and those trying to put out the massive fire? Absolutely!" she added. "These police officers tried many times to control the situation before they ultimately had to handcuff him in order to protect this man from himself.
"We probably all would instinctually react the same way, but handcuffing was truly needed. The fire was bad!"
"It's NOT 'My Life My Choice'," another added. "Because if they DID allow them to go in, and they got trapped, now some firefighter has to risk HIS ass to try and save them."
What's more, he said, there's legal liability, as well as the fact that public servants were trying to do their jobs protecting people and property.
Family members awoke to crackling noises shortly before 7 a.m. after flames from the Merritt Avenue shed fire spread to the home, the captain said.
One of them was cut jumping out a window, responders said.
The house partially collapsed in the rear. Flames also damaged a neighboring home and trailer.
The cause wasn't immediately determined.
Dumont police and firefighters responded and were joined by firefighters from Bergenfield, Cresskill, New Milford and Tenafly.
Because there were multiple injuries, the Bergen County Prosecutor's Arson Investigations Unit also responded, as did county animal control officers, Tamburro said.
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