Dorothy Walton holds the hand of Larry Walker as she leads neighbors in prayer in the 4000 block of West Potomac Avenue in Humboldt Park on June 27, following a fire two days before that left three young boys dead and one critically injured. | Colin Boyle/Block Club Chicago

The three boys killed in a West Humboldt Park fire June 25 were trapped in the family’s basement apartment as the blaze engulfed their home, unable to get out because the apartment’s only exit was blocked by smoke and flames, officials said.

The boys’ mother managed to escape through a window, but the boys were stuck in the apartment, inhaling deadly smoke, until firefighters got to them, Fire Department spokesman Larry Langford said.

Jayden Cruz, 6, and Angel Rodriguez, 11, died of their injuries Monday, officials confirmed. Axel Cruz, 4, died early Sunday, fire officials said. A fourth child is hospitalized in “extremely critical” condition, Langford said.

The boys’ mother and a man believed to be her boyfriend were also hospitalized. Langford couldn’t provide an update on the two adults’ conditions, but said the mother suffered from facial burns and smoke inhalation.

Ald. Emma Mitts (37th) is embraced by Dorothy Walton and Paula Thomas as neighbors gathered in the 4000 block of West Potomac Avenue in Humboldt Park for prayer on June 27, 2022 following a fire two days before that left three young boys dead and one critically injured. | Colin Boyle/Block Club Chicago

“From the looks of mom’s injuries, she probably made an attempt to get the kids out, but was literally burned in the process,” Langford said.

The fire struck the family’s garden apartment in the 4000 block of West Potomac Avenue. Firefighters responded just after midnight, pulling the children from the burning building and performing CPR on them in the parkway outside the apartment building.

Crews entered from the side of the building and broke basement windows to get the children out because there was “only one way out,” fire officials said. All four kids were in full cardiac arrest, officials said.

“Our response time was about three minutes. If they called right away, it would probably be three to four minutes in that smoke, which is a long time to be breathing in smoke,” Langford said.

The boys’ mother and her boyfriend were outside the apartment building when firefighters arrived.

Investigators believe the fire was accidental and was caused by an open flame in the apartment, but an investigation is ongoing, Langford said.

The community is rallying around the family in the wake of the tragedy.

Distraught neighbors and local leaders, including Ald. Emma Mitts (37th), held a vigil near the scene Monday afternoon, setting up a memorial with stuffed animals in the Children’s Garden of Hope, a community garden and park where the kids would often play.

“It was very, very heartbreaking. As a parent, it’s very hard. I don’t even want to imagine,” neighbor Jasmine Gomez said Tuesday afternoon near the memorial.

After Gomez and her family left, another neighbor stood at the memorial crying. She said her kids routinely played with Jayden, Angel and Axel in the park.

City and fire officials are continuing to investigate the landlord’s role in the tragedy.

Langford, the fire spokesman, said while the building had a working smoke detector, the family’s basement apartment did not.

The apartment building doesn’t have any open violations and there have been no recent calls of service, said Amanda Bolton, spokeswoman for the city’s Department of Buildings. The building’s only prior violation was in 2011 for plumbing issues, Bolton said.

Cook County property records show the building has three apartments, including the family’s basement apartment. The building’s landlord did not return calls for comment.