Dateline: Deadly Valentine - 5 harrowing details about Denise Leuthold's murder, revisited 

Denise Leuthold’s murder on Valentine’s Day 2013 still sends shivers down the spine, especially for true crime fans who caught it on Dateline.

The Dateline episode, Deadly Valentine, first aired in 2019 and appeared again on Dateline: Unforgettable in 2024. It takes a look at the day Denise, a mother of three from Peoria, Illinois, was killed, right when most people are celebrating love. Her husband, Nathan Leuthold, was behind it.

Denise’s murder is tangled up in a story about trust, faith, and hidden betrayal. Nathan and Denise had spent years as Baptist missionaries, even living overseas, before coming back to Illinois. On the surface, they seemed like a couple with a shared purpose. Underneath, though, Nathan was hiding an affair with Aina Dobilaite, a younger woman from Lithuania. The Leutholds had actually helped Aina come to the U.S. for school, which made the situation even messier.

When Denise was killed, Nathan tried to cover his tracks. He set things up to look like a break-in, and at first, police thought that was what happened. But as investigators dug deeper, the story started to unravel. The lies, the staged crime scene, the secret relationship, all of it pointed back to Nathan.

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Dateline: Five harrowing details about Denise Leuthold’s murder

The crime scene

Denise Leuthold died just inside the entryway of her Peoria home on February 14, 2013. Someone shot her in the head with a .40-caliber Glock, the same model her husband Nathan owned though he told police his gun was missing after the murder. Denise had come home from dropping off her youngest child at daycare. She barely got through the door. Detective Shawn Curry, who spoke about the case on Dateline, pointed out that Denise still wore her coat and gloves. She hadn’t even had a chance to settle in.

Detective Curry told Dateline: Unforgettable:

“She didn’t even have time to take her coat off, gloves, anything. So when she entered that door, that shot was immediate.”

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The staged burglary

Nathan called the police and claimed there had been a home invasion, insisting it was a random attack. But the scene told a different story. Kitchen cabinets stood open, drawers were pulled out, all arranged to look like a burglary. One detail didn’t fit: someone had used a spare set of car keys to move Denise’s vehicle to an abandoned park. That is not something a random burglar would do. The whole setup looked like a deliberate attempt to cover up the crime.

Her mom, Diane Newton, told Dateline:

“I work at a store that sold high-def TVs and we had a lot of small ones that they could have just picked up, taken away, you know, electronics, Blu-Ray players. None of those things were touched and I only had probably three rings that were of any value, but those three rings were taken. Well, why would a burglar know that those were the only three that were valuable?”

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Nathan’s computer searches

The case against Nathan got even stronger when investigators searched his computer. He had looked up things like “how to muffle a gun,” “hitting someone over the head to knock them out,” and “lethal injection.” These searches showed he wasn’t acting on impulse; he had planned this. For the jury, that digital trail sealed the deal.

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The affair

Behind it all was Nathan’s affair with Aina Dobilaite, a 21-year-old woman from Lithuania, whom the couple had helped bring to the U.S. for school. Prosecutors said Nathan killed Denise so he could be with Aina. Nathan spent time in places near her spas and hotels. The school even asked Aina to leave after concerns about her relationship with Nathan. Denise knew what was going on. Her diary entries showed her pain. According to Dateline, in one, she wrote:

“I know you want me dead. Why do you want to humiliate me by running around with a 20-year-old?”

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Conviction

In 2014, a jury took just 90 minutes to convict Nathan of first-degree murder. The evidence was overwhelming. He got 80 years in prison. Nathan’s defense tried to argue there was no real proof and denied any romance with Aina, but the jury and the judge weren’t buying it. During sentencing, Judge Kevin Lyons told Nathan he had “poisoned” an otherwise lawful life, calling out the betrayal and careful planning behind the crime. Nathan is now serving his sentence in Illinois.

Dateline reporter Andrea Canning was quoted as saying by Oxygen:

“So many of the stories I’ve covered haunt me. Often it’s the senseless loss I can’t shake, but this one sticks with me not just because of what happened, but when it happened. Maybe I’m a romantic, but I see Valentine’s Day as such a whimsical holiday. A day devoted to love and affection, but to those involved in this story, Valentine’s Day will forever be associated with cold-blooded murder.”