Dateline: Secrets Uncovered is examining the murder of Karen Duenas, who was stabbed to death by her husband, Mark Duenas, at their home in Cottonwood, northern California.
On the night of May 5, 2012, Karen was stabbed three times in her bedroom. She received two wounds to her back and a fatal one to her chest that severed her aorta and windpipe.
Her body was supposedly discovered by her husband, Mark, who called 911, telling the dispatcher his wife was covered in blood.
A recording was made of the 911 call, and Mark appeared to either say, “I gotta – I killed my wife. s**t. I mean, blood everywhere,” or “I gotta – I found my wife sick. I mean, blood everywhere.”
Mark insisted that he said the second version of those words, but the cops had an audio expert enhance the recording, which revealed he had said he “killed” his wife. The killer then claimed the police had altered the tape to incriminate him.
Karen and Mark had slept in different bedrooms due to Mark’s snoring and his getting up early. He claimed he heard a “crazy noise” that sounded like animals fighting, and when he went to investigate, he found his wife covered in blood.
The cops quickly suspected Mark Duenas had killed Karen Duenas
Mark said he then called 911 and turned his wife’s body over. The detectives immediately noticed that Mark had no blood on his clothes. He told them he’d been very careful when turning his wife over to avoid getting blood on himself; however, the cops suspect he changed his clothes after killing Karen.
Watch the Latest on our YouTube ChannelThe police learned Mark had been having an affair with a woman living in Idaho. Karen and the woman’s husband had recently found out about the affair, and the cheating pair had apologized to their spouses and agreed to cut off contact.
The woman in Idaho did cut off contact with Mark, but he appears to have messaged her on at least one other occasion.
Mark Duenas convicted of Karen Duenas murder in second trial
Mark was subsequently charged with murder. He has been on trial twice; the first trial ended in a hung jury after they were unable to agree on a verdict. However, a second trial ended in a conviction.
The killer was sentenced to 25 years to life in prison. He is currently housed in Folsom State Prison and will be eligible for parole from May 2030.
In 2022, Mark’s legal team lodged a petition challenging their client’s conviction on the grounds his original lawyer had failed to have blood experts and an audiologist testify on his behalf during the second trial. But Shasta County Judge Daniel Flynn struck down the petition ordering Mark to remain in prison.
Dateline: Secrets Uncovered airs Thursday at 9/8c on Oxygen.