"The individual was administered a COVID-19 vaccine several hours before their death on January 21, 2021. The vaccine was not administered by Placer County Public Health. There are multiple local, state, and Federal agencies actively investigating this case," the sheriff's office said in a Saturday statement released on Facebook.
The individual in question tested positive for COVID-19 in late December.
It is unclear which coronavirus vaccine was administered to the patient.
According to US media reports, the Placer County Coroner's Office will be conducting an autopsy by Monday.
Several European countries, including the Netherlands and Bulgaria, have reported instances of individuals suffering adverse side effects, such as swelling around the eyes and rashes, after receiving the Pfizer/BioNTech vaccine against the coronavirus.
Last week, a Belgium resident died five days after receiving the same vaccine; an investigation has been launched. An investigation is also ongoing in Norway after 23 people died after getting Pfizer/BioNTech shots.