Three-year-old Alexis Mercer died on February 9, 2015, in Lake Charles, Louisiana, after a handgun belonging to her father discharged. Reports describe the shooting as accidental; the child picked up the weapon and sustained a fatal wound. Emergency responders were called but Alexis did not survive.

The Calcasieu Parish Sheriff’s Office opened an investigation that focused on how a toddler could access a loaded firearm and on the weapon’s storage.

What details about the investigation or the circumstances of the firearm’s storage are still missing that might help explain how this tragedy happened?