Investigators are still seeking answers after a deadly explosion in northwest Indiana.

Investigators initially said a family at a home was going through a grandfather’s belongings Saturday night when they found a hand grenade and it exploded.

A man was killed and his 14-year old son and 18-year-old daughter were sent to the hospital.

Investigators are still trying to determine whether the device may have self detonated due to its age or other factors, or whether the pin was pulled.