(CNN) -- Four days after calling off a search for key evidence, investigators have located a mattress that they believe is important to their probe of a North Carolina girl who hasn't been seen for weeks.
The missing mattress, which belonged to 10-year-old Zahra Clare Baker, was thrown out by her parents in early October, days before she was reported missing, police say.
While authorities continue to look for Zahra's body, the search for the mattress itself was called off Friday. But on Tuesday, employees at Foothills Environmental Landfill in Lenoir, North Carolina, found the mattress and turned it over to investigators.
The bed contained DNA that will be tested to confirm it is indeed related to the Zahra Baker case, according to a statement from the Hickory, North Carolina, Police Department.
Authorities say the girl's disappearance is being investigated as a homicide.
She was reported missing October 9. But no one other than a family member has reported seeing her since September 25, when a woman saw her at a furniture store.
The missing girl's stepmother, Elisa Baker, who police said last week admitted to writing a fake ransom note the day after the girl's disappearance was reported, is now cooperating with investigators, Hickory police said.
Initially arrested on October 10 on several unrelated charges including writing worthless checks, Elisa Baker was additionally charged with obstruction of justice for leaving the note. That charge is a felony.
On Monday, Elisa Baker joined joined police as they searched for evidence at a site near a home she lived in three years ago.
Zahra's father, Adam Troy Baker, was arrested just past 3 a.m. Monday in nearby Catawba County on eight charges, including five counts of submitting worthless checks and three counts of failing to appear in court.
Police earlier acknowledged that Adam Baker faced bad-check charges, which are unrelated to the disappearance of his daughter. But they did not initially arrest him, as he had been helping authorities in their search.
Adam Baker was at Charlotte/Douglas International Airport picking up a family member Sunday before he voluntarily went to the Police Department in Hickory, about 60 miles northwest of Charlotte, to talk to authorities.
At the request of Adam Baker, who is an Australian citizen, the closest Australian consulate, which is in Atlanta, Georgia, was notified of his arrest.
The disappearance of Zahra, a freckle-faced youngster who wears a prosthetic leg and hearing aids, has made international news. The girl lost her leg to bone cancer, according to CNN affiliate WCNC-TV in Charlotte.
Family members and neighbors have told reporters that Zahra's stepmother abused her. Her attorney has denied the allegation.
Police also have said they had been in contact with Zahra's biological mother in Australia and asked for the girl's medical records.