Dateline: A Killing In Cottonwood- What happened to Karen Duenas? Details of the 2012 murder, explored

The Dateline episode titled A Killing in Cottonwood deals with the murder of Karen Duenas, a Californian mother of five in May 2012.

On a fateful morning Karen Duenas, a 34-year-old woman was discovered stabbed multiple times in her bedroom. Her unfortunate death was followed by an investigation that resulted in a popular trial. What happened to Karen is the mystery that Dateline ponders in this episode.

Investigators were quick to state that it was Mark Duenas her husband who killed Karen. However, the defense stated the murder was committed by an unknown intruder. What followed was a heavily publicized trial that revealed the true culprit.

Mark and Karen were high school sweethearts, from a Mormon family, who married as teenagers and had five boys Jason, Jacob, Tyler, Troy, and Cassey. Karen was a full-time mother while Mark was a UPS driver. However, on that fateful summer night in May 2012, the 'supposed' happy family was shattered by the death of the matriarch Karen Duenas.

Here are the details on what happened to Karen Duenas and what led to Mark Duenas as a prime suspect as shown in the Dateline episode titled A Killing in Cottonwood.

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What happened to Karen Duenas as shown in Dateline?

As shown in the Dateline episode, the murder of Karen Duenas was quite confusing. Investigators pointed their fingers at Mark Duenas who was stuck in a troubled marriage with Karen and also had an extra-marital affair.

Karen Duenas was found in her home on May 5, 2012, with severe stab wounds on her back and chest which damaged her blood vessels resulting in her death. Initially, the detectives thought it was done by some intruder but evidence pointed towards someone from the family. The authorities even found out that the couple's relationship was strained and Mark was texting his former lover.

Dateline also presented the theories put forward by the defense attorneys that it was an intruder who killed Karen. Evidence like the 911 call made by Mark Duenas and forensic blood reports became crucial in the case. In the 911 call Mark seemed like confessing to the crime in a mumbled voice he said, 'I got ah, I killed my wife, s--t, I'm blood everywhere." With the help of expert interviews and in-depth analysis, the Dateline episode explores the death of Karen Duenas and unravels the complexities.

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Mark Duenas was charged with the murder of his wife Karen Duenas as shown in Dateline

Mark Duenas was charged with the murder of his wife Karen Duenas. His troubled marriage, an extramarital affair with an ex-lover, and the fact that he was the last person to see her alive made him a primary suspect in the case. As shown in Dateline, Mark Duenas went through two publicized trials and it led to divided public opinion.

In the first trial, the jury was not able to come to a verdict. In the second trial, Mark Duenas was convicted of killing his wife and was given a 25-year life sentence in 2013. He was arrested five months after murdering his wife Karen Duenas in their Cottonworld home on May 5, 2012.

After nearly six years of being convicted in the Cottonworld murder case, Mark's lawyer asked for a new trial claiming the previous attorney couldn't gather enough evidence to defend him. They claimed that the previous attorney did not have blood experts and an audiologist to verify the evidence given by the prosecution.

However, the California 3rd District Court Appeal rejected the appeal in 2018. concluding that the legal issues that had been raised were properly raised during the trial.