Johannesburg - A father stabbed his 11-year-old son and threw his 3-year-old boy off a balcony in Hillbrow after an eight-hour hostage drama, Gauteng police said on Wednesday.Captain Tsekiso Mofokeng said the couple had an argument around 17:00 on Tuesday in their flat."The man stabbed the woman; and also the 11-year-old boy. The woman [aged 33] managed to flee and the police were called."Upon arrival, the police discovered that the father, 41, was with his 3-year-old son on the balcony and was threatening to throw the child from the sixth floor."We then sent in our hostage negotiator."Negotiations went on into the night, but at 01:15 on Wednesday morning, the man flung himself and toddler off the balcony."He threw the toddler from the balcony and he also jumped. He was certified dead on the scene."The 3-year-old survived the plunge and the police also managed to rescue the 11-year-old boy.The mother and the two boys were hospitalised.