(Portland, OR) -- Closing arguments have been heard in the trial of a Portland woman whose dogs attacked and killed a six-year-old boy. Koko Miller faces four felony charges, including criminally negligent homicide. Miller was watching the boy when her dogs mauled him to death in 2023. Prosecutors say Miller knew her dogs were dangerous around kids and failed to crate them. Miller's attorneys argue there's no evidence Miller knew her dogs were aggressive and this was just a tragedy.