Louisville fire officials are trying to determine the cause of weekend blaze that killed three children and two adults.Four of the victims died Saturday; the fifth, a ten month old child, died Sunday.The house fire at 1249 South Clay Street also injured four others.Officials says the blaze broke out in a first-floor living room.Louisville Fire and Rescue spokesperson Sal Melendez says investigators found one smoke detector on the second floor of the home.Some three dozen firefighters worked to extinguish the blaze.