A Fort Smith mother died early Friday of injuries from a Tuesday house fire, police said. She is the third person in the family to die in connection to the blaze. Fort Smith public information officer Aric Mitchell said 30-year-old Whitney Kaub died at 3:39 a.m. Friday. Two of her children, a 5-year-old boy and a 3-year-old girl, died earlier this week due to injuries from the fire. The blaze started about 3 a.m. Tuesday at a home on the 800 block of North 35th Street, according to a news release. Responders discovered Kaub and her four children inside. Police said the children were flown to Arkansas Children's Hospital in Little Rock. Mitchell said Friday that the two surviving children, 8- and 10-year-old girls, remain at the hospital receiving treatment for life-threatening injuries.