The head and skeletal remains found behind an Anne Arundel County bargain store on Monday are those of a young woman who was killed with blows to the upper body, according to police.

Authorities have ruled the death a homicide. Few other details, including the woman’s identity, are known, and police said they are using dental records and DNA to try to learn who she was. Police said that the remains had been behind the store for at least several months.

The remains belonged to a white woman with brown hair who was between 18 and 20 years old and was about 5 feet 6 inches tall, police said.

Justin Mulcahy, a spokesman for the Anne Arundel County Police Department, said the remains “do not appear to be matching up with any of our missing persons.”

The department lists six open missing-persons cases in the county, one dating to 1976.

The most recent is Jessica Lynn Lee, a 20-year-old last seen May 8 at a Shoppers Food store in the 5700 block of Ritchie Highway in Brooklyn Park, in northern Anne Arundel near the Baltimore City line.

She is described as a white woman with blond hair standing 5-foot-8 and weighing about 127 pounds.

Mulcahy said that on Thursday, police officers were back at the scene where the remains were found, in the 8100 block of Ritchie Highway in Pasadena.

“Now we’re trying to look for additional witnesses or evidence,” he said. “Certainly it’s difficult when dealing with remains. We’re not ruling anything out yet.”

A man walking near Ollie’s Bargain Outlet found the skull shortly before 3 p.m. Monday. Police searched the area with cadaver dogs from Chesapeake Search Dogs and Mason-Dixon Rescue Dogs and found more remains in the woods “a good distance away,” Mulcahy said.

Authorities would not say how much of the skeleton, or whether any other evidence, was found.

Maryland’s chief medical examiner, David R. Fowler, would not comment specifically on the case but said his office uses anthropologists with PhDs to examine human remains. Approximate age, sex and height can be determined by measuring the leg and pelvis, which differ in men and women. Joints age and wear differently in the sexes, for example.

Fowler also said that dental records, which police routinely collect after a person is reported missing, can be checked in at least two national databases.

Police and other authorities said that discoveries of human remains are unusual. But it’s the second such find in two days in Maryland. On Wednesday afternoon, the Frederick County Sheriff’s Department said a tree trimmer found skeletal remains 10 to 15 yards off the 4100 block of New Design Road in rural Western Maryland.