A house fire in the middle of the night on the Iron Range killed a husband, wife and two of their grandchildren, and left a third grandchild less seriously harmed, authorities said Wednesday.

The blaze in the 200 block of 42nd Street E. in a Hibbing neighborhood broke out shortly after 1:30 a.m. Tuesday, the Fire Department said.

Fire crews arrived to find one juvenile outside and four other people trapped inside, fire officials said.

The four were pulled from the fire on the south end of town about 15 minutes later and were not breathing. While the two children were resuscitated and hospitalized, the couple died, the Fire Department said.

Authorities later said one of the children died Tuesday and then another not long after at Hennepin County Medical Center in Minneapolis.

The husband and wife were officially identified Wednesday as Steven Gillitzer, 67, and 63-year-old Patricia Gillitzer.

Patricia and Steven Gillitzer

It was soon after the fire was extinguished that "we learned that this tragedy would strike us close to home," a department statement read, referring to Steven Gillitzer's nearly quarter-century as a Hibbing firefighter paramedic until his retirement in 2000.

Some in the department now worked with Gillitzer during his tenure, "adding a level of difficulty to an already devastating situation," the statement continued. Flags outside the Hibbing fire stations were at half-staff Tuesday afternoon in his memory.

The grandchildren who died were identified as Todd Gillitzer Jr., 9, and Isaiah Adams, 3. Surviving the blaze was Jonathan Gillitzer, 8.

Fire officials have not released a preliminary cause of the blaze, which left the house a total loss.

"The investigation is ongoing amongst the double-digit below-zero temperatures," a Fire Department statement read.