MUKILTEO — A Mukilteo woman was arrested Wednesday for investigation of assaulting and mistreating a 10-year-old girl who police described as “extremely emaciated” when she was removed from her home in August.

The girl was admitted to an Everett hospital Aug. 15 weighing 51 pounds — about t

wo-thirds the weight of a healthy child her age. Doctors reported that she was suffering from “severe malnutrition.” She also had multiple bruises, abrasions and scars all over her body, according to court papers.

The girl initially denied being mistreated. Since then, she has told police the woman burned her with cigarettes and beat her with a cord, belt and wire, according to a search warrant released Wednesday.

The woman and her boyfriend have been under investigation for allegedly withholding food from the girl.

Court papers identify the couple as the girl’s adoptive brother and the man’s girlfriend.

Her condition came to the attention of police after a store owner raised concerns with Child Protective Services about a child who came into the business. CPS was told the girl had a gash on her arm and a sunken face, and the outline of her bones were visible. The caller also said a woman with the girl was being “verbally abusive” toward the child.

Detectives with the Snohomish County Sheriff’s Office Special Investigation Unit assisted Mukilteo police in serving a search warrant on a home near the 4800 block of 103rd Place W. in Mukilteo on Wednesday morning.

The victim recently provided information while she was in a protected setting that led detectives to conduct a second search of the home to locate additional evidence, Mukilteo police officer Cheol Kang said.

“That provided the probable cause for the search warrant and arrest,” Kang said.

The girl was in the hospital for a couple of weeks and continues to get medical attention, Kang said.

The second search warrant filed Wednesday detailed the investigation since the girl was taken away from the home.

Doctors told investigators that the girl had cigarette burns on her wrist and the tops of her feet. She also had marks all over her stomach and chest that doctors said were likely from some sort of cord, according to the warrant. The girl also had a kidney infection. Doctors concluded that the girl likely was deprived of food and water.

The girl’s adoptive mother flew in from New York and visited her at the hospital. She told detectives that the girl didn’t look any different than she normally does. She explained that the girl took medication for fetal alcohol syndrome and that’s why she couldn’t gain weight.

Doctors, however, disagreed with the woman’s statement, saying that fetal alcohol syndrome is not the cause of her malnutrition. They noted that since she’d been hospitalized she rapidly gained weight, detectives wrote in the search warrant.

The girl initially told authorities that she was fed three meals a day and was treated well. She later told a social worker that if she talked, she was told that her brothers would be taken away from her and separated.

Then last week the girl allegedly talked to her foster mother and told her she’d been abused by her older brother’s girlfriend.

According to court documents, the girl said the woman burned her with cigarettes, beat her with electrical cords and stifled the girl’s screams by placing a rubber ball in her mouth. She said the woman had tried to drown her in a bathtub and threatened to kill her and dump her body in a lake.

The girl said she was forced to sleep in a bathtub. She also told investigators that she was locked out of the house and forced to sleep in a tent.

Detectives on Wednesday seized extension cords, a tent and a ball from the home.

It wasn’t the first time that state Child Protective Services had been called to investigate the family. In 2009, a boy, 16, asked to remain locked up at the Denney Juvenile Justice Center in Everett rather than return to live with the couple.

The boy told authorities he was fed only oatmeal and was beaten with a wooden paddle wrapped in leather if he didn’t follow house rules, according to a search warrant filed in August.

Court documents show that the couple denied the allegations raised in 2009. In a lengthy letter to a Snohomish County Superior Court judge, they admitted putting the boy on a “jail food diet” and making him sleep in a tent in the back yard to discipline him. They called the boy a “habitual liar and chronic runaway,” and detailed their efforts to provide him a stable home.

Eric Stevick: 425-339-3446, stevick@herald.com.