WEST ALLIS, WI (WTAQ) - Two boys were killed, and two other children were hurt in a Sunday morning duplex fire in the Milwaukee suburb of West Allis.

At a vigil Sunday night, family members identified the victims as 14-year-old Michael Gonzalez and 14-year-old Isaiha Kobow.

They said the children were burned so severely, that dental records will be needed to officially identify them.

Michael’s 13-year-old brother Joel Gonzalez was in fair condition at last word at Milwaukee Children’s Hospital. Their 4-year-old brother Kendall was expected to survive, but there was no word on his condition.

Relatives said the four youngsters were alone upstairs – and a downstairs’ resident knocked on the door and woke up Joel. Investigators said Joel rescued young Kendall and then went back inside to get the others – but he was stopped by the flames.

The Gonzalez brothers normally stayed with a grandmother, but they were at their mother’s house for the weekend. One relative said they were celebrating Joel’s birthday, which took place a few days earlier.

The state Fire Marshal and the U.S. Bureau of Alcohol, Tobacco, Firearms, and Explosives are helping West Allis authorities investigate the cause of the fire.