Indianapolis - Police say a four-year-old boy fatally shot his three-year-old playmate.

Lt Jeff Duhamell told The Indianapolis Star that the boy picked up a loaded .45-calibre handgun that had been left on a kitchen table in Fiona C Lee's house on Thursday and pointed it at the girl's head before firing.

Lee's daughter, Aunesti Lee Allen, died that day at Riley Hospital for Children.

Duhamell said on Friday that the boy is the son of Lee's boyfriend.

Police say they found cocaine and marijuana in Lee's home and arrested the 26-year-old woman on child neglect and drug charges. She was being held Friday in the Marion County Jail.

Duhamell said Lee's two other children witnessed the shooting. They are being cared for by a relative. - Sapa-AP