MOUNTAIN VIEW, Calif. (AP) — Officials say two people found dead at a California apartment filled with toxic gas have been identified as a father and his teenage son.

Authorities said Monday that 53-year-old Lian Liu and his 17-year-old son, William Liu, were found in the Mountain View apartment Wednesday after police and firefighters responded to reports of noxious fumes in the neighborhood.

Police say one of the victims died by suicide and the other died accidentally, but they would not say which one killed himself.

After authorities arrived at the scene, they evacuated several buildings and four officers were treated for exposure to fumes.

Officials say investigators determined that the fumes came from calcium sulfide and sulfuric acid, and did not come from a natural gas leak.

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