This is the second part of the series,"Escape from the Mayo Clinic." Read the first part here.

Sherburn, Minnesota (CNN)One winter afternoon last year, Duane Engebretson sat in his stepdaughter's hospital room at the Mayo Clinic in Rochester, Minnesota, trying to figure out how she could escape.

Alyssa Gilderhus, 18 and a senior in high school, had been a patient at Mayo for about two months, ever since having a ruptured brain aneurysm on Christmas Day.

https://cdn.cnn.com/cnnnext/dam/assets/180621204244-01-escape-from-mayo-03-alyssa-purple-shirt-large-169.jpg 460w, https://cdn.cnn.com/cnnnext/dam/assets/180621204244-01-escape-from-mayo-03-alyssa-purple-shirt-exlarge-169.jpg 780w, https://cdn.cnn.com/cnnnext/dam/assets/180621204244-01-escape-from-mayo-03-alyssa-purple-shirt-super-169.jpg 1100w," src="https://cdn.cnn.com/cnnnext/dam/assets/180621204244-01-escape-from-mayo-03-alyssa-purple-shirt-medium-plus-169.jpg" class="i-amphtml-fill-content i-amphtml-replaced-content">Alyssa Gilderhus before her ruptured brain aneursym and hospitilization at the Mayo Clinic.

Mayo neurosurgeons saved her life, but she and her parents were unhappy with the care she was receiving in the rehabilitation unit, and they say they repeatedly asked for her to be transferred.

But they say Mayo refused to let her transfer to another hospital, even after a lawyer wrote a letter asking Mayo to make the arrangements.

Alyssa and her family began to suspect that Mayo was trying to get a guardian appointed to make medical decisions for her. They were right: Hospital staffers would later tell police that they had gone to two county adult protection agencies to make guardianship arrangements.

https://cdn.cnn.com/cnnnext/dam/assets/180712104125-08-escape-from-mayo-medium-plus-169.jpg 307w, https://cdn.cnn.com/cnnnext/dam/assets/180712104125-08-escape-from-mayo-large-169.jpg 460w, https://cdn.cnn.com/cnnnext/dam/assets/180712104125-08-escape-from-mayo-exlarge-169.jpg 780w, https://cdn.cnn.com/cnnnext/dam/assets/180712104125-08-escape-from-mayo-super-169.jpg 1100w," src="https://cdn.cnn.com/cnnnext/dam/assets/180712104125-08-escape-from-mayo-medium-plus-169.jpg" class="i-amphtml-fill-content i-amphtml-replaced-content">Alyssa Gilderhus with her siblings at the Mayo Clinic.

Duane and his wife, Amber Engebretson, weren't sure how to get their daughter out of Mayo. Two nurses had been assigned to watch over her at all times.

But on February 28, 2017, an idea struck Duane as he sat in Alyssa's hospital room.

He looked at one of the nurses. She had been with them a few weeks before, when Alyssa's great-grandmother had come for a visit.

Betty Stalheim was 80. She'd just had knee surgery. She was fragile.

If he told the nurses that Grandma Betty wanted to visit but couldn't make it all the way upstairs to Alyssa's room, it might just sound believable, he figured.

He put his plan into action about 4 p.m., with his 9-year-old daughter, Allie, secretly videotaping with a small GoPro camera hidden in her hand. He told CNN he wanted the videotape to show that Alyssa had left the hospital willingly and that he hadn't been violent with staff, and to record actions taken by Mayo employees.

Duane told the nurses he wanted to take Alyssa downstairs to say hello to Grandma Betty in the lobby.

The video shows Duane pushing Alyssa in her wheelchair down the hospital hallway. She has a bandage on her neck where her breathing tube had been removed a few days before.

Two women in scrubs follow them.

When the group arrives in the lobby, there is no Grandma Betty.

Duane says he sees Grandma Betty's car at the entrance and walks out the hospital doors with the two staff members trailing behind him.

As he approaches the car, the front passenger door opens.

There is no Grandma Betty. She was never there. Instead, Alyssa's mother is in the driver's seat.

"Alyssa, we're going to go home, honey. Come on," Amber says to her daughter.

As Duane helps his stepdaughter out of the wheelchair and into the passenger seat, the two women in scrubs run toward her, and someone yells, "No!"

"Yes, she is! Yes, she is!" Duane and Amber yell back.

The video shows a hand grabbing Alyssa's arm as Duane helps her into the car. A nursing aide would later tell police she had tried to grab her.

"Get your hands off my daughter," Duane yells at the aide.

Duane closes the car door and gets in the back seat.

"Get out of here, Amber," he tells his wife. "Go, go, go, go, go, go!"

The car drives away from Mayo.

Recalling her escape some months later, Alyssa says it felt "phenomenal."

"It was like the biggest weight off my shoulders," she said.

'We have a patient abduction'

At 4:28 p.m., a Rochester Police dispatcher received a call from Mayo Clinic security.

"We have a patient abduction," the caller said.

An officer arrived on the scene 20 minutes later.

A Mayo social worker told him that Alyssa "cannot make decisions for herself" and that her mother couldn't care for her "because Amber has mental health issues."

The social worker also told police she "understood there was no formal diagnosis" for Amber.

Amber told CNN she has no history of mental illness and took offense to the social worker making such an unqualified pronouncement.

https://cdn.cnn.com/cnnnext/dam/assets/180712144627-18-escape-from-mayo-medium-plus-169.jpg 307w, https://cdn.cnn.com/cnnnext/dam/assets/180712144627-18-escape-from-mayo-large-169.jpg 460w, https://cdn.cnn.com/cnnnext/dam/assets/180712144627-18-escape-from-mayo-exlarge-169.jpg 780w, https://cdn.cnn.com/cnnnext/dam/assets/180712144627-18-escape-from-mayo-super-169.jpg 1100w," src="https://cdn.cnn.com/cnnnext/dam/assets/180712144627-18-escape-from-mayo-medium-plus-169.jpg" class="i-amphtml-fill-content i-amphtml-replaced-content">Alyssa Gilderhus as a child with her grandmother Betty Stalheim, mother, Amber Engebretson, and younger siblings.

"It's absolutely absurd," Amber said. "She said it to the police department. She has no reasoning. She has no justification."

The social worker told the police she'd been working with adult protection services in two Minnesota counties "trying to get emergency guardianship" but had been unable to get court orders to do so.

An Olmsted County Adult Protective Services official told police that "Mayo was requesting [assistance] in gaining guardianship of Alyssa because they were concerned for the mother's mental health and the medical decisions that were being made for Alyssa."

But something didn't quite make sense to John Sherwin, captain of investigations for the Rochester Police Department.

If Alyssa couldn't make decisions for herself, as the social worker had said, and if she needed a legal guardian appointed for her, then who had been making decisions for her while she was in the hospital?

When police asked that question of Mayo staffers, Sherwin said, they replied that Alyssa had been making her own medical decisions.

"When doctors were consulting with her in regards to her medical care, they weren't doing so through a guardian or someone that had been appointed by the courts. It was in direct contact with the patient," Sherwin said.

He said it became clear to investigators that Alyssa "in fact could make decisions on her own" -- including the decision to leave the hospital against medical advice.

"There was no abduction. This was done under her own will," he said. "You had a patient that left the hospital under their own planning."

Though satisfied that Alyssa was capable of making her own decisions, Sherwin still was concerned about her health.

"What was relayed to us [by Mayo staff] was that the patient was in danger of dying if they were not in the hospital," Sherwin said.

Mayo sent the police an order for a 72-hour hold, which allows police to admit someone to a hospital emergency room against their will if they're a danger to themselves.

But first, the police had to find Alyssa.

Police search for Alyssa

Alyssa and her parents were on the run. They weren't answering their cell phones, and they weren't at home, either.

They later told CNN they https://amp.cnn.com/cnn/2018/08/13/health/mayo-clinic-escape-2-eprise/index.html