LONGVIEW, Wash. (AP) — Police say authorities are working to identify skeletal human remains found in a southwestern Washington field Thursday.

A man found the remains while surveying a property for a construction project.

Longview police said Tuesday the remains haven’t been identified yet because of an advanced stage of decomposition.

Longview police detectives, the Cowlitz County Coroner’s Office and Cowlitz Search and Rescue worked through the weekend to process the scene.

The coroner’s office is working to identify the remains and determine a cause of death.