A suburban Detroit woman who police said was hearing voices was charged Monday in the stabbing deaths of her young daughters inside the mobile home they shared.

Jennifer Kukla was arraigned on two counts of first-degree murder in the deaths of Alexandria, 8, and Ashley, 5. If convicted as charged, Kukla, a 30-year-old resident of Macomb Township, faces a penalty of life in prison without the possibility of parole.

Police say Kukla acknowledged killing her daughters and that alcohol and drugs may have been factors.

Police, who were called to the home by Kukla's sister around 6 p.m. Sunday also found three dead Pomeranian dogs stacked atop one another inside a cage, as well as a dead pet mouse.

They have no motive for the deaths, which they say occurred around 7 a.m. Sunday.

"I don't think evil has an explanation, and it certainly doesn't explain itself," said William Cataldo, chief of homicide for the Macomb County prosecutor's office.

Kukla told the magistrate that she had a prior arrest for driving with a suspended license but never had been treated for mental illness. She was ordered held without bond.

The magistrate at the Shelby Township district court where Kukla was arraigned Monday afternoon initially set a date of Feb. 20 for her next court appearance.

At the mention of that date, Kukla and her sister, Elizabeth Lawrie, who was in attendance, both shouted out, saying that date was Ashley's birthday.

The magistrate then switched the date to Feb. 15, and Kukla thanked him. Kukla was not represented by an attorney at the hearing.

After the hearing, Lawrie expressed disbelief at the killings.

"There is a history of medical problems in my family," she said, without elaborating.

The scene inside the mobile home 30 miles northeast of Detroit was gruesome, county Sheriff Mark Hackel said. It was there that police recovered four large, bloodied kitchen knives in addition to the bodies.

Hackel said that an autopsy determined both girls died from multiple stab wounds to the throat areas. He said that Kukla told police both children were awake at the time they were stabbed.

The scene was "very difficult," Hackel said. "Even the officers were having a hard time with that one. ... That was one that left you with not much sleep last night, that's for sure."

Police were notified Sunday evening by one of Kukla's sisters — not Lawrie — after she visited the home.

"When she approached the door, the door was open already," Hackel said. "She called her sister's name, she came out to the door area and she explained that she had harmed the kids."

Hackel said the sister never entered the dwelling. She told police she had visited her sister Saturday night to help her clean the house out of concern for her sister's children, the sheriff said. She reported leaving around 11 p.m.

The sister told police she was concerned about some of her sister's comments Saturday night, "although nothing to indicate that she would do something to this extent," Hackel said.

Authorities said they had contacted the fathers of both daughters, one of whom is in prison on an unknown offense. Hackel said neither had much contact with the girls.