CASTAIC, Calif. (AP) — Detectives investigating the disappearance of a Los Angeles woman are searching a landfill northwest of the city.

The Police Department says investigators served a search warrant Monday in the disappearance of Heidi Planck to excavate a specific area of the Chiquita Canyon Landfill in Castaic for human remains and evidence.

Planck was reported missing by her ex-husband on Oct. 20.

Detectives found that she was last seen on Oct. 17 in downtown Los Angeles at an apartment complex where her dog was found.

Unspecified evidence led police to believe something happened there resulting in her death.

Her car was found in a garage several blocks away and further investigation led investigators to the landfill.