A construction crew digging up a house foundation to prepare for construction of a shopping center turned up a plastic bag full of human bones, apparently from a killing decades ago, authorities said.

The badly deteriorated bones, which did not include a skull, were found Monday and the cause of death remained under investigation, but sheriff's Detective Ed Troyer said it appeared to be a homicide.

"They didn't get there by themselves," Troyer said. "Someone put them there."

He said the remains apparently had been in the ground for 25 to 35 years before the bag was uncovered by a large excavator on the shopping mall project.

Detective Capt. Richard D. Adamson said the excavator may have scattered some pieces of bone which apparently were buried between the house and a detached garage. Much of the construction site was cordoned off Tuesday as evidence technicians used a wire-mesh screen to sift dirt for more bone fragments.

Property records and missing-person reports dating back more than three decades also were being examined, Adamson said.

Daniel Carlson, who lives next door to the construction site, said the property where the bones were found has been in his family for decades and was occupied by his aunt and uncle for many years before it was converted to a rental property in the late 1970s.

After being occupied by a series of renters, many of them college students, the house was shuttered about a year ago when his cousins decided to commercially develop the land, Carlson said, adding that he never heard of any trouble there.

In neighboring Thurston County, sheriff's detectives on Tuesday released more information on a human skeleton, skull included, that was found in March on a logging trail near Cedar Flats, west of Olympia. Those bones apparently were at the site for one to five years, a forensic anthropologist with the King County medical examiner's office in Seattle said.

The bones are from a man at least 50 years old, about 5-foot-9 to 6 feet, and possibly Caucasian mixed with Asian, Hispanic or American Indian, the anthropologist found. The man may have walked bent over because the bottom eight vertebrae of his spine were fused.

Investigators have been unable whether death was from suicide, homicide, an accident or natural causes but have said the discovery of the remains in a remote area is suspicious.