'Help, help me': Man stabbed his scientist wife with kitchen knife to 'put her out of her misery' as his mother 'begged' him to stop, cops say

Left: James Martin (Johnson County Jail). Right: Amber Martin (Amber Martin/Facebook).

New details have emerged in the case of an Iowa man accused of hatching a plan to kill his wife and then ultimately following through on doing so.

James Martin, 47, has been charged with first-degree murder in the death of 41-year-old Amber Martin. He was jailed in January in the Johnson County Jail under a $1 million bond.

On Jan. 16, on the 2800 block of Spring Rose Circle in Coralville, Iowa, James Martin was planning to kill his wife.

"In the hours leading up to the defendant killing the victim, the defendant formulated a plan to kill the victim," detectives wrote in a criminal complaint obtained by Law&Crime. "The defendant retrieved a kitchen knife and surprised the victim as she exited another room and stabbed the victim repeatedly."

Police arrived at the apartment in Coralville, which lies in the eastern part of the state, around 6:40 a.m. that day due to reports of a stabbing. When they entered, officers found Amber Martin with multiple stab wounds. She was pronounced dead at the scene.

This week, authorities released additional details in the case — namely that James Martin's mother was reportedly a witness to the harrowing attack.

According to Cedar Rapids-based ABC affiliate KCRG, the mother told officers that she arrived at the apartment around 1:00 a.m. that morning due to her son's mental health "spiraling." She said she fell asleep on the couch but woke up to noises from the laundry room.

She reportedly thought it was the couple's cat, but then heard the words, "help, help me." She approached, and though there was no light on, she allegedly could see her son stabbing her daughter-in-law.

The mother is said to have rushed into the room and "begged" James Martin to stop. When he did, she could not find her phone and asked him to call the police.

Officers said that when they entered the home, they found a a bloody knife in the kitchen sink as well as smears of blood and bloody clothing in the home. James Martin admitted to killing his wife, the complaint stated.

The suspect was arrested, and investigators sought to uncover a motive.

They say James Martin told them he stabbed his wife to "put her out of her misery," per KCRG. He reportedly believed they were in financial trouble that they could not come back from.

Amber Martin worked as a medical laboratory scientist supervisor for the University of Iowa Health Care system. Her boss, Connie Floerchinger, told Muddy River News that they were "shocked and horrified" by her death, adding that she was "sweet, smart and had an amazing personality."

David Harris contributed to this report.