A Missouri man has been charged with three counts of first-degree murder after police in Kansas City said he shot dead his ex-girlfriend for hurling a diaper at him and then killed her toddler son and current boyfriend.The victims in the September 8 slaughter have been identified by police as 17-year-old high school senior Bianca Fletcher, her 1-year-old son JoJo and her 18-year-old boyfriend Shannon Rollins Jr.Fletcher's 16-year-old brother, Brandon, was the one who discovered the three lifeless bodies after returning home from work just before 9.30pm last Tuesday.Police who were called to the scene in the 5900 block of East 84th Street found no signs of forced entry and no shell casings, but some of the victims' personal belongings were missing, according court documents.The following day, 22-year-old Joseph Nelson walked into a local police station to report the theft of two firearms, a magazine and ammunition from his vehicle. At that point, multiple witnesses stepped forward and identified Nelson as the gunman in the triple homicide.According to one witness, Nelson came to him after the killings and confessed to shooting Fletcher after she threw her son's diaper at him during an argument. The alleged killer then asked his acquaintance for advice on how to handle the situation.Court records cited by the station KCTV indicate that after gunning down the young woman, her son and her boyfriend, the 22-year-old picked up all the shell casings, showered several times and washed his hands with bleach.He later also sold the murder weapon, according to documents.Another witness told investigators that Nelson said to him:'I did something bad. I did something I don't think I can live with. I killed them. I killed them.'Asked why he shot Fletcher's toddler son and her boyfriend, Nelson allegedly replied: 'witnesses.'He added that little JoJo was crying and he killed him so the neighbors wouldn't hear.Fletcher's sister, Rebecca, told the station KMBC the 17-year-old mother was a senior at Raytown High School and dreamed of becoming a doctor. Her son had just turned one and was learning to walk.Shannon Rollins was an aspiring dancer who had recently performed with local rapper Tech N9ne.Richard Fletcher, Bianca's father, said in a statement that the 18-year-old was 'a very good influence' on his daughter and will be missed by all.Nelson was charged Thursday with three counts of murder, armed criminal action and burglary. Prosecutors asked a judge to set the suspect's bail at $1million. Click here to read full news..