Woman Gets 41 Years for Stabbing Death of Mother-In-Law

April 6, 2014— -- A 20-year-old Colorado Springs woman has been sentenced to 41 years in prison for the gruesome stabbing murder of her mother-in-law, authorities said.

Ellyzabeth Rainey was sentenced Friday after pleading guilty in January to the second-degree murder of her husband's mother, Deborah Rainey, 59, whom she killed by throwing boiling water on her, hurling free weights at her head, stabbing her and pouring bleach into her mouth and nose.

The events took place in April 2013 at Ellyzabeth Rainey's apartment in the Tanager Meadows complex in southeast Colorado Springs, where she lived with her husband Jason Rainey and newborn baby, according to an affidavit signed by a Colorado Springs police detective.

At the time, the couple's relationship was deteriorating and they were about to get a divorce, police said. Deborah Rainey had been staying at the house for two weeks to help take care of the couple's 2-month-old baby.

"Ms Rainey commented that Deborah has never liked her anyway … she got tired of being pushed around so 'she killed her,'" Det. Shawn Peterson said in the affidavit.

Investigators said Ellyzabeth Rainey had long quarreled with her mother-in-law and had been hospitalized recently for "hallucinating." The 20-year-old said "voices" told her that her mother-in-law was going to take everything away from her.

On April 3, Ellyzabeth Rainey invited her moter-in-law for a home-cooked dinner, then violently killed the woman and covered her body with an air mattress before her husband came home from work.

Ellyzabeth Rainey admitted to boiling hot water and throwing it on her mother-in-law while she was sitting on the couch to "distract her," police said. She then threw her husband's loose weights at Deborah Rainey's head and stabbed her multiple times in the stomach, heart and throat to make sure she was dead. At some point, Rainey forced bleach into the woman's mouth and nostrils.

When police arrived at the apartment to respond to a noise complaint from a neighbor, they heard a baby crying and went inside the home where they saw a bloody butcher's knife lying on the kitchen counter.

Ellyzabeth Rainey picked up the baby and told officers to take the child because she was about to run. When they asked why, Rainey said "because I just killed someone," police said.

Rainey then threw the baby at one of the officers before bolting, said police. One of the officers caught up with Rainey further down the street, while another went inside the house and discovered the body.

At the station, police noted the woman smelled strongly of bleach and took a statement from Rainey, in which she admitted she had been diagnosed as bipolar when she was 10, but did not take any medication, police said.

ABC News was unable to reach Jason Rainey or Ellyzabeth Rainey's attorney, Todd Johnson, for comment.