A 47-year-old man from Iowa is accused of plotting to murder his wife and then carrying out the plan by stabbing her multiple times in their residence, authorities report.

James Martin faces charges of first-degree murder following the death of his 41-year-old wife, Amber Martin, in Coralville, near Iowa City. Police were called to an apartment in the 2800 block of Spring Rose Circle around 6:40 a.m. on Friday after receiving a report of a stabbing incident. Upon arrival, officers discovered Amber Martin suffering from multiple stab wounds.

Emergency responders declared her dead at the scene.

According to a criminal complaint accessed by Law&Crime, James Martin confessed to the murder of his wife.

“In the hours before the attack, the defendant devised a plan to kill the victim,” investigators stated. “He obtained a kitchen knife, caught the victim by surprise as she left another room, and stabbed her repeatedly.”

Cops took the suspect into custody after evidence was consistent with James Martin”s statements and observations by a witness. Detectives did not publicly divulge a possible motive for the attack.

The victim worked as a medical laboratory scientist supervisor for the University of Iowa Health Care system.

“My entire staff and I are shocked and horrified by Amber’s death,” her boss Connie Floerchinger told Muddy River News. “She was sweet, smart and had an amazing personality. She had only been with us since September but we all feel like we had known her forever! Our community and the field of clinical microbiology will not be the same without her.”

Before that, both the victim and her husband reportedly worked for the Quincy Medical Group as medical researchers. Ann Ostermiller told Muddy River News she trained Amber Martin in her position.

“Amber was such a wonderful woman,” she told the outlet. “She was vivacious, kind, and loved by all her coworkers. Jim was quieter and more reserved. This murder is beyond the comprehension of those that knew them when she worked at QMG. They seemed to be such a close and loving couple. I cannot imagine what transpired to change their relationship so much.”

James Martin is at the Johnson County Jail on a $1 million bond.