It happened in the area of "D" and Ellis Streets around 11 Monday morning.
The sheriff's office received a 911 call from an employee of a carpet cleaning company doing scheduled work inside a home.
The employee said he saw a father and son struggling over a firearm -- and the son asked the worker to call authorities.
When deputies arrived, they found the 63-year-old son dead inside the home.
The 86-year-old father was taken to the hospital for evaluation.
Nearby schools were placed on lockdown as a precaution.
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