A mother was arrested Tuesday on suspicion of involuntary manslaughter after her 2-year-old son drowned during a bath at a home in Placentia. “Her statement to investigators was that she stepped away for a short period to grab something,” added Placentia Police Department Lt. Joe Connell. The mother was also taken to a hospital for treatment of unspecified self-inflicted injuries, Connell said. “The investigation revealed that the mother was giving the child a bath in a walk-in shower, using a plastic storage bin,” according to Connell. “The mother walked out of the bathroom to obtain some soap and left the child alone for approximately 2 minutes.