A Missouri nurse is accused of poisoning her husband with antifreeze, then torching her family home as part of an alleged plot to wed a prisoner.

Amy Lynn Murray, 40, is charged with first-degree murder, arson and other alleged crimes in connection to the death of Joshua Murray, who was killed in December. The couple was married for about 15 years and had an 11-year-old son, records show.

According to police, Murray was in the throes of a romantic relationship with a convicted killer at Jefferson City Correctional Facility, where she worked. That inmate, Eugene Claypool, is serving a life sentence for fatally stabbing a 72-year-old lottery winner on Christmas Day in 2000, and apparently knew about Joshua’s slaying.

“It just doesn’t seem like something that she would have done,” one family friend told The Daily Beast of the allegations against Murray.

“I just know that she was raised good, she came from a good home and got a good education,” the friend added. “What triggered this, I have no idea.”

Authorities say Murray ignited the blaze at her Iberia residence, then drove to a McDonald’s in Osage Beach with her son and two dogs. Cellphone records show Murray was at the house 30 minutes before a dispatcher received the call about the house fire on Janice Drive, a probable cause statement alleges.

Murray told investigators that her house was in flames when she returned from her fast-food trip. She knew Joshua was inside, but heavy smoke prevented her from accessing the residence, court papers state.

The alleged killer was captured on security footage entering the McDonald’s drive-thru at 11:48 p.m. and receiving a beverage and bag of food. Police say that a sandwich was later found on the kitchen counter of the home, and a McDonald’s bag was in the trash.

Miller County Sheriff Louie Gregoire said that investigators knew the fire was suspicious “pretty much immediately” after entering the master bedroom where Joshua’s body was found. “An accelerant was used,” Gregoire told The Daily Beast.

On Dec. 11 at 2:08 a.m., police responded to a call about a fire at the Murray residence and discovered the body of 37-year-old Joshua on a bed. According to the probable cause statement, fire officials ruled out accidental causes and determined the fire originated from the bed and was contained to the bedroom.

Meanwhile, the Boone County Medical Examiner ruled Joshua likely died of ethylene glycol poisoning and was dead before the blaze started. (Ethylene glycol is a colorless and odorless chemical, and the primary ingredient in antifreeze.)

During their investigation, sheriff’s investigators recorded phone calls between Murray and Claypool in which she “talks about not wanting to be around her husband” and “wanting a divorce from him,” the probable cause statement says.

“Amy Murray talks about not wanting Joshua Murray to come home from Nebraska and she is tired of being around him,” the document continues. “Amy Murray talked about her and Eugene Claypool now being able to get married because Joshua Murray was deceased.”

The couple discussed embarking on a new life together now that Joshua was dead, and finding an attorney for Claypool so he could get out of prison early, court papers state.

An obituary for Joshua indicated he married Murray in June 2003 and that he worked most recently as a construction supervisor.