A 75-year-old man was killed and six others were injured Sunday after a large fire engulfed an apartment building in DeKalb County, officials said.

At least three dozen people were displaced in the blaze, which broke out around 11:30 a.m. at the Park Creek Apartments on Bouldercrest Road, according to DeKalb fire spokesperson Capt. Jaeson Daniels.

Responding firefighters encountered heavy flames and saw several residents leap from the 24-unit building, which is one of several at the complex, officials said.

“We even heard that people were jumping from the third floor,” Daniels said. “So that’s what was going on when we actually arrived.”

Knowing some of the residents had tried to rescue themselves by jumping, firefighters immediately began searching apartments where they believed some residents were likely in need of help. In other apartments, they had to wait to enter until it was safe.

Crews found the deceased victim inside one of the apartments. He was identified as William Arnold by the DeKalb County Medical Examiner’s Office.

Officials said four of the injured people were taken to the hospital with burns and various injuries, though their conditions are unknown at this time.

The American Red Cross was at the scene Sunday to help provide relief efforts to 36 people impacted by the fire. Daniels noted that some of the apartments had been empty at the time.

“There could be more displaced, I only have the number of people the Red Cross has assisted from this fire. Sometimes residents decline assistance, sometimes they aren’t home and we haven’t reached them yet, etc.,” Red Cross spokesperson Katie Zwerk told the AJC.

A backhoe arrived late Sunday afternoon to clear debris and help fire investigators, officials said. The complex is a short distance from I-285 in Gresham Park.

Daniels said the cause of the fire is under investigation.