DES MOINES, Iowa (AP) — The death of a woman found fatally stabbed in a rural Iowa farmhouse near Early has been ruled a homicide, authorities said Monday.

Marilyn Schmitt, 45, was found dead Thursday in an upstairs bedroom of her home, about 100 miles northwest of Des Moines. An autopsy revealed she had been stabbed, Sac County Sheriff Ken McClure said in a statement. The criminal complaint says Schmitt was stabbed between 1:30 a.m. and 5:45 a.m.

Schmitt’s son, 21-year-old Kirk Riley Levin, has been charged with first-degree murder.

“Kirk Levin admits to law enforcement that he was the only one who could have killed the victim,” the complaint, which detailed the charge, said. “Kirk Levin admitted that he choked his mother and that he had to have killed her.”

Levin’s court-appointed attorney, Charles Schulte, of Sac City, did not immediately return a call.

Levin was arrested Thursday after a 21-year-old woman claimed he kidnapped her. The woman told investigators Levin was an acquaintance and showed up at her home in Storm Lake at around 6:30 a.m. Thursday, saying his car had broken down and that he needed a ride to his home in Early, about 15 miles away.

She said after arriving at the farmhouse, Levin took her to a barn, tied her up with a rope, put her in the trunk of his car, and then took her out and put her in the back seat, McClure said. While driving away, his car skidded on ice and went into a ditch. When a neighbor stopped to offer help, Levin ran, the woman said.

Deputies found him hiding in a barn about a mile away. When investigators went to the farmhouse, they found Schmitt’s body, McClure said.

Levin also is charged with assault with intent to commit sexual assault, assault while participating in a felony, and third-degree kidnapping.

Schmitt bought the home and a few acres with outbuildings in October 2007, and McClure said Levin lived there with her until he went to prison in 2010 for third-degree burglary.

Levin was released New Year’s Day after serving a little more than two years of a five-year sentence, Iowa Department of Corrections spokesman Fred Scaletta said. Iowa prison terms are frequently reduced if inmates stay out of trouble while incarcerated.

Levin was scheduled to appear in court Tuesday morning for a bond hearing on the kidnapping and assault charges, Sac County Attorney Ben Smith said.

An initial appearance also now will be held on the murder charge.

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