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About two dozen people were forced to evacuate from an East Chatham apartment building early Monday after a fire that police say was intentionally set tore through the complex, injuring one man.

Firefighters were called to the 8200 block of South Drexel Avenue on the South Side about 2:10 a.m. and soon elevated it to a second-alarm fire, sending additional crews to the scene. They located a 53-year-old man who was suffering from the effects of smoke inhalation and took him to Jackson Park Hospital for treatment, according to a media notification from Chicago police.

Police said approximately 20 people evacuated the building. Larry Langford, spokesman for the Chicago Fire Department, said most, if not all, of the residents who evacuated the building did so on their own before firefighters arrived, including the man who suffered minor injuries.

Langford said the Office of Fire Investigations, or OFI, determined the fire had actually been set in a stairwell, likely between the first and second floors.

“It went up the stairs and it affected more than one unit,” he said. “The manner and location of the fire were considered suspicious by the OFI and they turned it over to police for further investigation.”

In cases when a fire potentially becomes a crime, it’s the Police Department’s job to work with OFI, which takes the lead on determining the cause of a fire, although only police can determine if that cause was also criminal.

“We do the science and they do the suspects,” Langford said. “We tell them where it started, how it started, then they figure out why it started — why did somebody do it, was it accidental or was it intentional?”

But by regulation, fire officials cannot make a determination of whether a fire was arson, he said.

“We can tell them a candle started the fire and they’ve got to figure out who lit the candle and why. We can narrow it down but we can’t do motive,” Langford said.

Asked what led to the determination the fire had been intentionally set, a police spokesman first directed questions to the Fire Department and when pressed said in an email: “According to the Chicago police report, Office of Fire Investigations related the fire to be arson.”

The blaze was eventually extinguished about 3:30 a.m., according to a post from the Fire Department on Twitter.

It was at least the third serious fire that led to displaced residents in Chicago in the past week, two of which resulted in fatalities. This weekend 81-year-old Venacio Delfino, a Northwest Side resident of a two-flat in the 5100 block of West Grand Avenue in Cragin, died when the building caught fire Saturday night. Residents of multiple units were displaced by the blaze, officials said.

When that happens, Langford said, “We call Red Cross, Salvation Army, and we call Human Services and between all of them they find places for the folks to go to that are displaced on a temporary basis.”

Another fire in the 3100 block of North Marmora Avenue in Belmont Cragin on Thursday left a 37-year-old man dead and three others, including a Chicago firefighter, in critical condition. The resident who died was identified as Eladio Luis Gomez Jr., according to the Cook County medical examiner’s office. A verified GoFundMe account was started to assist his surviving family members, including his mother and sister, with unexpected expenses. The entry on the fundraising site read in part: “Eladio was an amazing young man who was so caring and loving to so many people.”

Monday afternoon Langford said the Chicago firefighter was “still very critical.”

In Cicero, another firefighter was injured while battling a blaze early Friday morning. He was hospitalized with first- and second-degree burns after he fell through the first floor to the basement while fighting a house fire in the 5400 block of West 30th Place, and three other firefighters suffered minor burns rescuing him, said Cicero spokesman Ray Hanania.

Langford said many fires in Chicago in December and January happen because people are trying to keep their homes warm in winter.

“They’re using stoves for heat, they’re using space heaters — that’s one of the major causes — electrical systems get overloaded,” Langford said, adding that on occasion people will use propane or charcoal grills indoors in an effort to keep warm, unaware of the danger. “It’s just a bad time of year.”

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