(CNN) Olivia Gant was a local celebrity, a terminally ill 7-year-old who spent her final months riding along with police and firefighters and taking on criminals at a Denver-area school as "the bat princess."

But it was all part of a lie, prosecutors say.

The girl was never terminally ill; it was her mother who killed her, a grand jury has found.

In an indictment unsealed this week, Olivia's mother -- Kelly Turner, aka Kelly Gant -- is charged with two counts of first-degree murder in her daughter's 2017 death. She is charged with two counts because Colorado law has a special provision when someone in a position of trust is charged with killing a child younger than 12.

Turner also faces a count of child abuse and 10 other charges related to her alleged bilking of Medicaid, hospitals and charities, including the Make-A-Wish Foundation, out of more than a half million dollars.

Following last week's indictment, which came on the heels of a yearlong investigation, the Douglas County Sheriff's Office arrested Turner on Friday at a hotel in Glendale, Colorado.

Doctors' doubts spur probe

Suspicions first arose when Turner brought Olivia's big sister to Children's Hospital Colorado in Aurora and informed a doctor that the older daughter, a minor whose name is redacted from the indictment, had been treated for cancer when the family lived in Texas, the indictment states.

The doctor confirmed this was not true, according to the indictment. Hospital officials later found articles, blogs, social media posts and news stories in which Turner said the older daughter suffered from various conditions, including bone pain, that weren't supported by medical records, the indictment says.

In an October 2018 interview with detectives, the girl said she'd had an unknown type of cancer. How did she know? Her mother had told her so, she told investigators, according to the indictment.

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A caseworker conducted a test in which the girl was separated from Turner to determine if she actually had medical issues. Once separated, the older daughter had no medical issues or complaints of pain, according to the indictment.

This raised concerns about Olivia's death, which hospital officials told investigators was "somewhat controversial with different doctors," the indictment says.

"There is a concern that (Turner) has lied about the children's medical conditions and therefore may have caused harm to the children and or caused them to have significant medical procedures," the indictment says, conveying doctors' reports to investigators.

The doctors also worried that Turner was concocting the children's conditions for social and monetary gain, the indictment says.

Talking to investigators, Turner "specifically denied ever fabricating medical conditions for her children."

Public defender Ara Ohanian told CNN he had no comment on his client's case.

Olivia's manner of death 'undetermined'

Olivia's extensive treatment history began when she was 2, doctors told investigators. She had autism and suffered from constipation, feeding intolerance and seizures. She received intense treatment -- including feeding tubes and an ostomy bag -- because of her problems eating, the indictment says.

She died in August 2017 of intestinal failure after Turner signed a do-not-resuscitate order, telling doctors that Olivia's quality of life was too poor to keep her alive, according to the indictment.

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In November, authorities exhumed Olivia's body, and the Arapahoe County coroner found "a lack of any anatomical findings" indicating that the girl had died from intestinal failure or that she had suffered from many of the conditions Turner reported, the indictment says.

"The manner of death is best certified as undetermined," the coroner wrote.

Though the indictment does not specify how prosecutors believe Turner killed Olivia, investigators noted that during an interview with Turner, the mother "spontaneously" broached the subject of Munchausen syndrome by proxy, a mental health disorder in which a caregiver makes up or causes injury to a child.

"That has never been my case, like, at all, whatsoever. You can talk to anyone that stood by my side through Olivia and all of this," Turner told detectives, according to the indictment.

If she had anything to hide, she wouldn't be talking to police or signing medical release forms, she said, though she eventually admitted lying about her daughter's cancer diagnosis, the indictment says. The rest of her daughter's conditions, she said, were legitimate.

Doctor 'shocked' Olivia died

Following the November autopsy, investigators began revisiting doctors who had treated Turner's children. Physicians recalled conversations in which Turner insisted Olivia suffered from conditions their examinations didn't support, the indictment says. Six doctors said that nothing for which Olivia was treated constituted a terminal illness.

Among the investigators' other findings, prosecutors say:

• A pediatric neurologist recalled telling Turner that Olivia didn't suffer from seizures and instructing Turner three times in two years to stop giving the girl seizure medication, but she did not.

• A Children's Hospital doctor said he told Turner she was incorrect in stating that Olivia was "rejecting" one of her feeding tubes and suggested reducing her dependency on the tube, but Turner refused.

• A gastrointestinal physician said Turner insisted on the do-not-resuscitate order for Olivia, which he signed, only to learn later the girl was receiving heavy doses of narcotics of which her pain management team was not aware.

• A pediatric anesthesiologist said when Turner proposed withdrawing all of Olivia's medical care, she was given other options but insisted, even in the face of "pushback" from an ethics team.

• A pediatric gastrointestinal doctor told detectives all of Olivia's symptoms and history "came from Turner" and that Olivia "did not exhibit the symptoms Turner described most of the time." He described the girl as "interactive, social and fun to be around." Another gastrointestinal specialist said the same thing about Olivia and her mother and was "shocked" to learn the girl had died after being taken off medical treatment.

* A gastroenterologist told investigators that he explained to Turner that one of Olivia's tubes and her ostomy bag could be removed and that she could live a somewhat normal life, but Turner refused, saying, "It's already been done." He, too, expressed surprise that Olivia had died.

The bat princess

That Turner peddled the story of Olivia's illnesses is well documented.

series of 2014 blog posts from her mother lays out a litany of health issues she says the girl, then 4, was suffering and touts an upcoming benefit to "help this sweet little girl with all the hospital bills she is incurring."

Local media documented her ride-alongs with police and firefighters , requests granted to fulfill the little girl's wish of serving her community.

"She's in intestinal failure and we don't know how much longer she has," her mother told a reporter during one segment . "We made a bucket list, and one of her things was to become a firefighter."

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In February 2017, Make-A-Wish Colorado posted a story about Olivia transforming into "the bat princess" and battling ne'er-do-wells. She vanquished villains and rescued the Chatfield High School mascot and two princesses, the organization reported, noting the charade was arranged to lift the spirits of the girl "battling a rare medical condition."

"You could give me all the money in the world, and I would give it back to you to be able to watch that day again," Turner was quoted as saying.

Even in death, Olivia's obituary was rife with references to her "rare disease." It spoke of how she always returned from operations and hospital stays with a smile. She loved Dairy Queen, zoos, dinosaurs and entertaining others, and it was only in the month before her August 20, 2017, death that her gregariousness waned, the obituary said.

"Our precious little princess will now have a new body, no tubes, no more pain or sickness and everlasting joy with our Lord," it said.

Indictment lays out almost $600K in fraud

According to the indictment, Turner fleeced 161 GoFundMe donors out of $22,270. Make-A-Wish told detectives it spent $11,265 on the bat princess event. A local charity reported giving Turner $3,000 for funeral expenses, while a funeral home told police Turner never paid her $5,398 bill, the indictment says.

GoFundMe told CNN this week that it had banned Turner's account and will issue refunds to donors, while Make-A-Wish said it was disturbed by the allegations.

"As we seek to learn more about the circumstances that led to Olivia's death, we fondly remember her spirit and hope that granting her wish brought some joy to her tragic life," the charity said.

Detectives also learned that Medicaid paid out $538,992 in benefits over almost five years, despite Turner's husband working for a company that would've provided health insurance to his wife and children.

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Jeff Gant, who stayed behind in Texas when his family moved to Colorado in 2013, also told police that he'd been making biweekly deposits of $1,800 each into a bank account Turner controlled. Gant further said Turner had asked him to take her and the girls off of his insurance because she'd found a better deal, the indictment says.

Turner told police in a separate interview that her husband's insurance wouldn't cover Olivia's pre-existing condition, the indictment says, and in a 2013 application for public assistance she said she was divorced from Gant, whom she described as an "absent parent."

In addition to the murder and child abuse counts Turner faces, she is also charged with two counts of forgery, two counts of attempting to influence a public servant, three counts of theft and three counts of charitable fraud.

"I am extremely proud and impressed with the determination of all agencies involved, especially my detectives. While it has been an extremely emotional case, they have investigated all aspects of it with diligence and professionalism," Douglas County Sheriff Tony Spurlock said in a statement.