Update: July 7 at 4 p.m. Rachel Sweet pleaded guilty in Osage County Circuit Court to first-degree involuntary manslaughter and child endangerment. The 28-year-old faces up to 10 years in prison for the drowning death of her infant son in a bathtub earlier this year.Sweet's 2-month-old son drowned in March when he was left unattended in a bathtub. Investigators said they believed Sweet put the baby in the tub and then fell asleep. He was found face down in the water.Sentencing is scheduled for Sept. 2.Original Story:The case of a Linn mother accused in the drowning death of her infant son continues.Rachel Sweet has a plea hearing Thursday morning in Osage County Court. Sweet is charged with involuntary manslaughter and child endangerment.Sweet TMs baby drowned in a bathtub in March.The 28-year-old has pled not guilty.