PHOENIX — Phoenix police say approximately 280 officers from 12 city, state and federal law enforcement agencies examined 21,500 tons (19,504 metric tons) of landfill material in an unsuccessful 12-week search for remains of a missing woman believed to be a homicide victim.

The search for Christine Mustafa ended after cadaver dog teams spent four weeks searching just outside the part of the landfill considered her body’s most probable location.

Daily teams of 32 officers previously spent each weekday from last October to late December scouring the primary search area.

Mustafa was reported missing May 11. Her ex-boyfriend, 38-year-old Robert John Interval, awaits trial after pleading not guilty in June to first-degree murder.

Sgt. Alan Pfohl says police are still tallying costs for the search, which included 23,650 hours of work.