Authorities said Thursday they've hit a roadblock in obtaining valuable information in the disappearance of a 38-year-old Oregon mother because they cannot prove a crime has been committed.
Jennifer Huston, of Dundee, Ore., was last seen on surveillance camera leaving a gas station in Newberg, a Portland suburb, one week ago. She and her vehicle have not been seen since -- despite expansive searches by air and land for the stay-at-home mom.
Capt. Jeff Kosmicki of the Newberg-Dundee Police Department told FoxNews.com Thursday that investigators are unable to obtain medical records and cellphone tower information because there is no evidence of a crime.
"It's impossible," Kosmicki said.
He also noted that detectives viewed security footage of Huston withdrawing money from an ATM, but said detectives cannot physically obtain the video because of lack of proof a crime has been committed. The video is valuable, Kosmicki said, because it provides the clearest images of Huston on the day she disappeared and could help solve the case if released to the public.
"We aren't able to have that video in our hands from the bank," he said.
Huston's cellphone shut off at approximately 6:35 p.m., but investigators don't know if it was turned off or if the battery died. Kosmicki said the last cellphone tower it pinged from was north of the gas station but "more technical" data is needed, like "latitude and longitude" information that might show which direction she was headed in.
More aerial searches are being conducted Thursday and Friday in Yamhill County for any signs of Huston and her 1999 dark green Lexus LX 470 SUV.
On Wednesday, sheriff's deputies directed an aerial search along the Willamette River -- from Wilsonville to Dayton -- while her family organized a fly over from Wilsonville Road and the Willamette River, Kosmicki said. The aerial searches have so far yielded no clues. Kosmicki said Huston's vehicle would be able to travel 300 to 350 miles on a full tank of gas.
Huston, a mother of two, was captured on surveillance tape leaving a Circle K gas station in nearby Newberg on July 24 at approximately 6:22 p.m. Since then, detectives have been poring over security footage along a Portland-area highway Huston would have traveled after leaving the gas station.
Bill Turner, Jennifer Huston's father and a former homicide investigator, said Wednesday that his daughter "probably went for a walk" after leaving her home to run errands, a day after detectives discovered she had purchased trail mix, Gatorade and non-lethal sleeping pills at a pharmacy shortly before her disappearance.
Turner declined to say whether he thought foul play was suspected and said his daughter may have taken a walk somewhere before she vanished nearly a week ago.
"She probably went for a walk," Turner told Fox News on Wednesday. "And she's unable to come home at this point in time."
"I don't want to even go there," he said, when asked about the possibility of foul play.
Huston left her home around 5:45 p.m. on Thursday to run errands, according to her husband. Detectives say she withdrew a small sum of money from an ATM before purchasing items at a pharmacy and then filling up her SUV with gas.
Huston's husband, Kallen, who passed a polygraph test, said his wife had complained of a headache for "several days" prior to her disappearance.
Detectives released new images Tuesday night of Huston entering a Rite Aid drug store about 3 miles from her home. She used the cash she had just withdrawn from the Oregon First Community Credit Union in Newberg to purchase items, which included over-the-counter sleeping pills. Police said the amount of sleeping pills she purchased would not be enough for a lethal dose.
Kallen Huston said earlier this week that his wife might have driven off the road and urged motorists to look for any signs of his wife and her vehicle.
"I have a feeling maybe she's in a ditch somewhere," he said. "We've exercised every option that we can think of right now."
The gas station security footage shows Huston purchasing gas between 6:10 and 6:22 p.m. on Thursday. Turner said he reviewed the footage with police and that it did not show anyone inside the vehicle with his daughter.
"There was nobody in the passenger's seat," Turner said. "We went through all the different camera angles and there was also no movement in the backseat."
Kosmicki confirmed that no one is seen inside the vehicle with Jennifer, but noted the footage "is not the best quality."
"She just handed her debit card over and the attendant pumped the gas for her," Kosmicki said of Huston, who has two sons, ages 3 and 6.
Kosmicki said the surveillance video taken from the bank showed Jennifer withdrawing cash from an ATM just before 6 p.m.
"It's a much better video. You can clearly see her facial details," he said. "Based on her actions, she seemed pretty calm." He said the video showed her opening the door slightly to finish her transaction.
No activity has been recorded on Huston's bank cards, according to police. Kosmicki noted that Huston's vehicle did not have a tracking device.
A Facebook page set up in the search for Huston says she was last seen wearing black and pink Nike shoes and black yoga pants. Her vehicle, a 1999 Lexus LX 470, has an Oregon license plate of WXH 011.
Anyone with information is urged to call the Newberg-Dundee Police Department at 503-538-8321.
Cristina Corbin is a Fox News reporter based in New York. Follow her on Twitter @CristinaCorbin.