"This is currently a coroner's case, and we don't have further details at this time. It will be up to the coroner to determine the manner and cause of death," Urena said.
The sheriff's office said it was unable to provide further information on the case at the moment, but that Apple's campus is open.
Urena said that Santa Clara County Coroner's investigators would conduct an autopsy to ascertain the cause and manner of death. She said authorities were not searching for any suspects.
The San Jose Mercury News, citing emergency dispatch calls, said initial calls to police reported a man with a head wound.
Dispatch audio posted on the newspaper's website also shows that the unidentified victim was found in a conference room on the campus with a gun.
Recode and others later reported that Apple had released a statement, in which it called the death a "tragic loss of a young and talented coworker," and said Apple was working to support the man's family, friends and coworkers.
The so-called Infinite Loop campus was calm on a cold and windy day in suburban Cupertino. A vehicle for the Santa Clara County Sheriff's Department could be spotted in the parking lot, as well as a handful of white Apple security vehicles with flashing yellow lights on top.
The Infinite Loop campus is the hub for Apple's vast workforce in Cupertino, which numbers 16,000 employees, according to a 2013 report on the company's economic impact. The company is constructing another campus in the city, a massive loop of glass often likened to a spaceship.
— CNBC's Mary Catherine Wellons, NBC's Chiara Sottile, and Reuters contributed to this report.