BERKELEY, Calif. (WTVO) — A human skeleton was found in an unused building on the University of California, Berkeley campus last week, and college officials are not sure how long it has been there.

Campus police investigated the remains, which were found in the unused residential hall complex and event space about a mile from the main campus on January 10, according to ABC News.

“Although the remains are skeletonized, it is not clear how many years they have been there,” a University of California, Berkeley spokesperson said in a statement.

The cause of death is currently being investigated by the Alameda County coroner.

“We understand that there are many questions and we anticipate that the coroner’s report will provide additional information,” the spokesperson said. “We do not anticipate this investigation will disrupt resident activities at the Clark Kerr Campus.”