BLACK DIAMOND, Wash. -- Sheriff's deputies have arrested a man for investigation of homicide by abuse after his emaciated mother was found dead.

King County sheriff spokesman John Urquhart said Christopher Wise, 41, called police about 1 a.m. Tuesday to say his 88-year-old mother had died.

Medics went to the house in the 27400 block of the SE Green River Gorge Road and said the woman, Ruby Wise, weighed only about 70 pounds and was suffering from severe bed sores and bruises.

"Clearly this was not just someone who died of old age," Urquhart said. "The woman clearly should have been in a hospital."

Woman hadn't seen doctor for years

According to the statement of probable cause, the medics found several extremely deep and open bed sores on Ruby Wise that exposed her bones. The woman was also extremely emaciated with "no apparent muscle or fatty mass," the document said.

The woman was wearing a hospital gown and an adult diaper, which was heavily soiled, statement said, and lying in a dusty bedroom in between bed sheets that were stained with dried blood, urine, feces and possibly pus.

Detectives noted that there was no phone in her bedroom, and only "minimal food items" in the refrigerator.

Christopher Wise told investigators he had been the sole caregiver of his mother for the past 10 years. He said he'd been living with her since September 2004.

The man said his mother suffered from an equilibrium problem that prompted her to fall occasionally, but otherwise had no medical conditions other than "getting old," the document said. He told investigators that his mother hadn't seen a doctor in at least two years.

Ruby Wise began showing signs of dementia about six months ago, her son said, and began needing adult diapers about three months ago. Christopher Wise said he changed her diaper every day or every day and a half, the statement said.

When she could no longer get out of bed, Christopher Wise began washing her in bed with an "alcohol rub bath," the last of which took place on Saturday, he told investigators.

The man fed his mother every two hours, giving her bread soaked in juice, half a banana and a little Snickers bar, detectives said.

Several weeks ago Ruby Wise said "she was ready to go to see dad and to just let her be," Christopher Wise told detectives, and hasn't wanted to be touched since last week.

On the night of her death, Christopher Wise said he had returned home after being gone for about eight hours to find her "wailing," the statement said. The man said she'd been doing that for some time. He said he checked in on her and fed her a banana. When he checked on her later, he saw that she was gasping for breath. He said he held her hand, and after she passed away, called 911.

Medics who responded to the call said Ruby Wise was "already cold to the touch," the document said.

Initial autopsy determined Ruby Wise died from pressure ulcers ("extensive" bed sores) on her body from the rotting skin and other complications from these injuries.

Neighbors: Woman's wailing was constant

The Wises' next-door neighbors told investigators they often heard Ruby Wise yelling and moaning for help for hours, and that the cries sounded "like she is not being cared for or starved," according to the statement.

The cries began in April 2009 and were "an everyday occurrence," the neighbors told detectives. When they brought it to Christopher Wise's attention, he later explained his mother had fallen out of bed.

Urquhart said there is no doubt the woman suffered.

"The seriousness of the bed sores, the bruising, the fact that she probably hadn't been eating -- yeah, I think it's safe to say that she had suffered," he said.

Christopher Wise was booked into the King County Jail on Wednesday evening after being interviewed again by detectives. Prosecutors plan to file charges, and asked the judge for a high bail in court on Thursday, calling him a flight risk.

"He doesn't have any income at this time because he was reliant entirely upon his mother for support," said Deputy Prosecutor Fletcher Evans. "He faces a very serious potential penalty on this matter, which is manslaughter in the first degree."

The judge set bail at $250,000.

Christopher Wise, who is said to be a college graduate with a mechanical engineering degree, told detectives during his interview "he guessed he should have got more help for her," the statement said.