The wife of a Chicago firefighter and their three children have died from injuries sustained a fire that broke out at their home last week.

Walter Stewart, the firefighter, was on duty when the house fire erupted Tuesday and rushed back to his residence in the city’s Montclare neighborhood to perform CPR on his wife, CBS Chicago reported, although he was not one of the crew members originally assigned to respond. Stewart’s name and service role was identified by the Chicago Fire Fighters Union Local 2, according to the station.

Stewart’s 7-year-old son, Ezra Stewart, was pronounced dead on Wednesday night, the Cook County Medical Examiner’s office confirmed. His wife, 36-year-old Summer Day-Stewart, died on Thursday evening

Summer Day-Stewart, 36, died days after in a house fire in the Montclare neighborhood. Her three children also died in the fire. Day-Stewart’s husband, an active Chicago firefighter, performed CPR on his wife after he rushed to the scene, after learning about the fire.

Photo supplied to CBS

At the time, the firefighter’s two other young children, identified by the medical examiner’s office as 2-year-old Emory Day-Stewart and 9-year-old Autumn Day-Stewart, were hospitalized in critical condition with injuries linked to the fire. The two children died on Friday night, according to the county medical examiner.

Officials at the fire department previously said that all four members of Stewart’s family had suffered from smoke inhalation during the blaze, CBS Chicago reported. Autopsy results with definitive causes of death for Stewart’s wife and children were not yet finalized when the station published its latest report about the house fire. 

Exactly what caused the fire to spark last Tuesday night inside the family’s home, located in the northwest section of Chicago, is still unknown and remains under investigation. Larry Langford, a spokesperson for the Chicago Fire Department, told the Associated Press that the fire began in the home’s kitchen. A spokesperson also told CBS Chicago that the fire department is coordinating with the medical examiner’s office as they work to determine how it happened. 

On Friday, firefighters distributed smoke detectors and other fire prevention materials to people living in Stewart’s neighborhood, which CBS Chicago said is common following a deadly blaze. Stewart’s family home did have smoke detectors, according to the station.

The Chicago Fire Department has launched a fundraiser through its charity, called Ignite the Spirit, to help Stewart’s family in the wake of the tragedy. The Fire Fighters Local 2 Union issued a statement in support of the family.

“Every member of Local 2 and the Department mourns with our brother Walter and the Stewart family. This tragedy weighs heavy on our hearts, and we pledge our ongoing support,” said Jim Tracy, the president of local 2, in the statement. “Local 2 is encouraging everyone to make a donation for Walter and the Stewart family through the ‘Ignite The Spirit Chicago.'”