Authorities in Pennsylvania say a 44-year-old woman is expected to spend decades behind bars for a fatal attack on her boyfriend earlier this year.

According to Fox News, Windi C. Thomas pleaded guilty to stabbing 44-year-old Keeno Butler and beating him with a table leg on March 18 before crushing him to death under the weight of her 300-pound frame.

Butler, who reportedly weighed less than half of his girlfriend, was found with knife wounds and a head injury after Thomas contacted authorities.

A medical examination found that he died as a result of “homicide caused by respiratory insufficiency secondary to blunt force trauma to the neck and thoracic compression, exacerbated by blunt force trauma to the head.”

His sister spoke out ahead of a sentencing hearing set for later this month, as reported by the Erie Times News.

“I feel like she should have 40 or more [years in prison],” Sandra Butler said. “She deserved life.”

She said her family continues to struggle with the loss, which has been especially tough on some relatives in particular.

“My mother, she calls for him every night,” Sandra Butler said.

As of the latest reports available, Thomas remained behind bars at the Erie County Prison.

In exchange for her guilty plea on one count of third-degree murder, prosecutors dropped related charges of aggravated assault, reckless endangerment and possession of an instrument used in a crime.

She is expected to face between 18 and 36 years behind bars. Her attorney, Mark Del Duca, said the sentencing recommendations are “fair for both sides” and represented “a good result based upon the facts of the case.”

[Featured image: Windi Thomas, Erie County Police Department]