The family of a man who was found dead at the Oregon Zoo on Monday told police he was missing two days earlier after he disappeared while attending a zoo concert with them. But they didn't file an official report until the next day.

62-year-old Carl Stanley Ross Sr. went to the Zoo Saturday night to see the performer George Clinton & Parliament Funkadelic, The Oregonian first reported.

Carl Stanley Ross Sr.
Carl Stanley Ross Sr.

Portland Police spokesperson Carlos Ibarra says Ross was reported missing by his family the day after the concert, on Aug. 11. Around 10 am on Aug. 12, Ross was found dead in the construction site of the new rhinoceros habitat by a worker. No animals were present in the exhibit at the time.

On Aug. 11, at 8:31 pm, the day after the George Clinton concert, the zoo was alerted by PPB that Ross had been reported missing, zoo spokesperson Hova Najarian tells WW. Najarian says the zoo later learned that Ross' family had filed a missing person report earlier that day at 5:43 pm.

"A police officer left our public safety manager a voicemail with a description of a missing person, and asked the zoo to call them if we had any information," Najarian says. "The recording did not indicate that this person might still be on zoo grounds and was not presented to us as urgent."

He adds that the zoo's public safety manager gave Ross' description to staff and asked them to be on the lookout. But, he says "security did not see anyone during their closing rounds."

When adults of diminished capacity or children are reported missing to zoo security, Najarian says protocol is to alert staff via an all-channel radio call.

"Everyone on radio looks for the missing person until they're found," Najarian says. "If they are not located within 30 minutes they are considered missing — all zoo staff then take part in the search and the police are notified. For other adults who become separated, we offer suggestions and assistance to help reunite the parties."

Najarian says zoo security records indicate that no one was searching for Ross the night of the concert, so typical protocol was not initiated.

He adds: "We are currently interviewing all staff and volunteers who were working the event that evening in an effort to learn more."

Ibarra, PPB's spokesperson, says the case is now being investigated by the medical examiner's office.