Investigators with the Office of State Fire Marshal and the Bureau of Alcohol, Tobacco, Firearms and Explosives prepare Wednesday to enter a home at 11 Olympia St. in Portland. The home burned on March 6, killing Doug Grant and injuring four others. Daryn Slover/Portland Press Herald

As the oldest of five children, Brendan Grant said he expected to be seen as his siblings’ protector. But it was his younger brother — the middle child — who assumed that role naturally.

Doug Grant, 36, died in a house fire at 11 Olympia St. in Portland in March. His brother and father described him as a kindhearted man who loved his friends and family, including his 10-year-old daughter, Judy.

Doug Grant, right, and his 10-year-old daughter, Judy. Photo courtesy of Scott Grant

“If you asked any of the siblings, they’re not supposed to say who’s their favorite, but they would all say Doug,” said Brendan Grant, 40, who lives in Georgia.

The Office of State Fire Marshal began an intense search of the burned-out home Tuesday after releasing Doug Grant’s name for the first time. A few technicians were still on scene Wednesday morning, sifting through the rubble upstairs.

Several agencies are assisting investigators, including the Bureau of Alcohol, Tobacco, Firearms and Explosives — a detail that concerns Doug Grant’s family members, who say they want answers about why the fire started and are frustrated they don’t know more about the investigation nearly two months after he died. Brendan Grant said his brother’s death had been deemed an accident in the autopsy report, but the search of the home now contradicts that.

Five people were in the building when the blaze was reported around 1:15 a.m. on March 6.

Brendan Grant said the autopsy report shows that his brother had inhaled smoke and suffered serious burns all over his body, but that the report raises other questions about how and why he died.

The other four people were taken to the hospital with various injuries. One person was recently released after being treated in critical condition, according to state Department of Public Safety spokesperson Shannon Moss.

An investigator with the Office of State Fire Marshal exits 11 Olympia St. in Portland on Wednesday. Daryn Slover/Portland Press Herald

Doug’s father, Scott Grant, said he didn’t know much about the other people who lived with his son but understood that they lived in separate rooms.

According to city records, it was a single-family home. Moss declined to provide further details about the layout of the building or the housemates’ relationships. She also declined to share why the search warrant is being carried out now and whether the fire is considered suspicious, saying the investigation is ongoing.

Scott Grant said he misses his son’s dedicated, helpful nature. He said the family was proud that Doug had been sober from alcohol for four years.

“Doug was very helpful in being a support system for me,” he said. “He stayed in touch regularly and if I needed something, he was happy to be able to do it.”

Growing up, Doug played football, joined the band and participated in school plays. He was a curious sibling with a sharp wit who loved making his family laugh at the dinner table, Brendan Grant said. And he was a fierce advocate when his older brother, who has autism, was being bullied.

“He was always so quick to defend and speak up for him in really powerful ways,” Brendan Grant said. “He would make sure that my brother was respected. I think that’s really important.”

Doug Grant most recently worked as a cook at The Moose, a sports pub in Falmouth, his family said. Outside of his shifts, Doug Grant filled his days by playing video games and spending time with his siblings and his daughter, who was “the light of his life,” said his father.

When Doug Grant learned he was going to be a father, his brother said he started rummaging through yard sales to find DVDs that they loved as children so he could share them with her one day.

“What he was really passionate about was sharing stuff he liked with her,” said Brendan Grant.

He named Judy after his mom, who died of cancer when Doug was 8 years old. Scott Grant said he will always remember his son’s deep “black olive” eyes, which he shared with his mother.