(CNN) Employees at the State Line Lookout Cafe in Palisades Interstate Park in Alpine, New Jersey, got a surprise when they went to work on Monday.

Hanging on the door was a bag of human bones.

The employees contacted the Palisades Interstate Parkway Police Department to report what they suspected was a bag of human remains, which has since been confirmed.

The Bergen County Prosecutor's office has launched an official investigation.

"The remains will be submitted to a lab for identification and will be compared to missing persons records," Bergen County Prosecutor Mark Musella said in a statement.

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