The Sacramento County Coroner identified bones found by a worker in Isleton as human Tuesday afternoon.
The remains were discovered Monday when crews were digging to install a sewer line at the Hotel Del Rio on 2nd Street. It was unclear how old the bones were.
Experts must now examine the bones to see if there was any foul play. If so, the case would be sent to homicide detectives.
It was unknown how long the bones had been there.