They call it society's latest dirty little secret, one that most people don't want to admit is happening: beating and neglecting grandma or grandpa.

But this week's criminal case stemming from the death of Lucille Tinker underscores a growing societal problem in desperate need of more attention, officials say.

"People are not even close to being aware of how many elder adults are being abused or neglected in Utah and what an issue it is," said Carrie Searcy, an investigator with the state's Adult Protective Services. "Even with the numbers we do have, it is grossly underreported and is just a small fraction of what is happening out there."

Tinker, 86, was just 59 pounds when police officers found her body on the floor behind her bedroom door this summer.

On Tuesday prosecutors filed a second-degree felony charge of aggravated abuse of an elder adult against Susan Christin Alexander, a granddaughter who had been Tinker's caretaker for 2 1/2 years.

According to charging documents, Alexander told authorities Tinker had been unable to feed herself, stand or sit up on her own the last two weeks of her life. She allegedly shut the woman in the room and did not return until she knew she was dead. Alexander also admitted she put a note on her grandmother's bedroom door falsely indicating she had already fed and bathed the woman so other family members would stay away, court documents said.

So far this year, state investigators have probed 413 other cases of "caretaker" neglect or abuse. Overall, the agency investigates 2,300 cases annually arising from complaints of abuse, neglect or exploitation of an elderly or disabled person.

"We are where Child Protective Services was 20 years ago and the issue of domestic violence was 15 years ago," said Adult Protective Services Assistant Director Ron Stromberg. "People are in that kind of denial: Nobody would ever hurt Grandma, how can this happen? It has been hidden for years."

Searcy, who has worked in the elderly community for 12 years, has seen a vast array of neglect and abuse cases:

• One woman lived in the back room of her son's home for years, leaving only to use the bathroom or she would be screamed at by another individual.

• One man had two black eyes that investigators said were a result of his wife beating him.

• A woman who allowed her son to be the "payee" for her Social Security check was too intimidated to ask for money for a bus pass because her son would grill her about her finances. Instead, she stayed home all day, isolated.

A recent revision to Utah's law on elderly and disabled abuse allows prosecutors to file criminal charges even in the case of emotional abuse, which includes forced isolation of the victim.