Investigators have exhausted leads in the mysterious disappearance of an elderly, medically fragile North Whidbey woman who hasn’t been seen since June.

“We’ve hit a wall,” Detective Ed Wallace with the Island County Sheriff’s Office admitted.

Betty Tews, an 81-year-old resident of Sonic Lane, went missing sometime prior to June 21. Wallace said investigators believe foul play may have been involved in her disappearance and they have identified “a person of interest” in the case, but they’re not naming the individual.

Tews, however, previously sought protection orders against her 55-year-old son, Raymond Willey, who had been living with her. She had accused him in court papers of pointing a gun at her head. Detectives reported that Willey was evasive about his mother’s whereabouts after she disappeared and then he suddenly left the state.

Investigators searched Tews’ densely wooded property and the property of her neighbors, but found nothing. Wallace said a dog team was brought in, but the canines didn’t pick up a trail. Detectives obtained a warrant to search the house, her vehicles and analyzed her computer for clues; again, they didn’t find anything. They’ve monitored her bank account, but there’s been no activity.

The investigators interviewed neighbors, friends and family, but nobody could help them find Tews. She has medical problems and is in need of daily medicine, but hasn’t refilled her prescriptions.

“It’s like she disappeared into thin air for the most part,” Wallace said. “We’re kind of at a dead end right now. We’re run through the entire investigative gamut with this.”

Tews’ rambler on Sonic Lane, a private road, is surrounded by woods and is out of sight of neighbors. One neighbor, who didn’t want her name to be used, described Tews as a tiny, frail woman who could also be very feisty. There’s a story about Tews standing in front of a bulldozer to stop it from going onto her land.

The neighbor said Tews’ son kept her isolated and turned away any neighbors who tried to help the elderly woman. Her husband, Glenn, died in 2009.

The neighbor said it’s both scary and sad to have a neighbor disappear so mysteriously. She said her daughters used to enjoy walking in the woods, but now they’re not allowed to go out there.

“We like to think Whidbey is our own little paradise, so this is upsetting,” she said.

Tews’ relatives on the mainland reported her missing in June after they hadn’t heard from her in a couple of weeks. Willey was living with her at the time.

Wallace said deputies repeatedly contacted Willey to ask about his mother’s whereabouts and he offered “many different excuses” about why she wasn’t home. At first he said she was visiting a friend.

“His stories kept getting less plausible and less plausible and at one point he wasn’t there anymore,” Wallace said.

Wallace indicated that Willey left town before detectives had a chance to interview him in any detail. Since then, Willey was arrested in California on suspicion of DUI, court documents indicate.

Willey is supposed to return to Whidbey Island next month for a hearing on a court case. He is facing a second-degree assault charge for allegedly stabbing a man in the head.

According to the police report, Willey attacked the man in his car Feb. 18 in Oak Harbor, apparently because he was upset with Tews.

The alleged victim reported that he accepted a ride home, but Willey pulled over during the drive and spoke on his cell phone with his mother. Tews had just kicked him out of her house, which angered Willey. The report indicates that the phone call upset Willey and that he suddenly attacked his passenger after hanging up. Willey allegedly stabbed the man in the head and face with a pocket knife, the report states.

Court documents show that Tews filed two petitions for “vulnerable adult orders for protection” against Willey, who has lived with her off and on for years.

Tews filed her first petition in Island County Superior Court on March 11, 2010. She wrote that she wanted Willey out of her home because she was afraid of him.

“I feel the respondent will act out in revenge and may harm me,” she wrote. “He will not leave my home when asked. He shows signs of paranoia — mixed with alcohol use and loaded weapons. I am fearful with him in my house.”

Tews claimed that she fell and broke her hip at home, but Willey would not help her. He told her that her hip wasn’t broken and that she should stop “squealing like a stuck pig,” she wrote. She lay on the ground for two hours before managing to call a friend for help.

Tews wrote that she has several handguns and rifles in the room that Willey occupies. She wrote that he told her he loaded all the guns and brought one into the kitchen for her.

“I am unclear of his motive,” she wrote.

Tews also wrote that she wanted law enforcement to help her secure her credit cards and her will.

Island County Superior Court Judge Vickie Churchill granted a temporary order and later a permanent “vulnerable adult order for protection” that barred Willey from his mother’s home or from having any contact with her.

Then on May 18, Tews filed a motion to terminate the order. She wrote that her stepdaughter wouldn’t let her drive her car, so she needed Willey to get her mail, put her trash out and shop for her. As a result, the judge terminated the protection order.

But again on Sept. 21, Tews filed a second petition for a vulnerable adult protection order.

In the petition, Tews wrote that a week earlier Willey spent the day drinking, pointed a rifle at her head and told her to say goodbye. She claimed she tried to knock the gun out of his hands and bruised her arm. She attached a photo of her bruised arm, apparently taken at Whidbey General Hospital.

In addition, she wrote that her son refused to take her to medical appointments. She claimed she was having chest pains one day and he refused to help her or bring her the phone; she found that her Lifeline device was disabled, she wrote. Also, she claimed that Willey made her give him money.

The judge approved the temporary order and set the hearing for the permanent protection order for Sept. 29. Tews didn’t show up for the hearing, however, and the judge dismissed the petition. The temporary order expired on that day.

Wallace said investigators didn’t locate any firearms when they searched Tews’ home.