This story originally aired on Dec. 2, 2023. At 6:30 a.

m. on April 25, 2010, Heidi Firkus called 911 after her husband, Nick Firkus, said an intruder was breaking into their Saint Paul, Minnesota, home. She was shot and killed.

Nick Firkus told investigators that his gun discharged when he struggled with the intruder – but something in his story struck police as odd. "It never felt right," Sgt. Nichole Sipes of the Saint Paul Police Department tells "48 Hours" contributor Jamie Yuccas.

"The story never made sense to me." A SHOOTING AT THE FRONT DOOR Sgt. Nichole Sipes : Well, this area of Saint Paul, where Heidi and Nick Firkus lived, I would characterize as generally a quiet neighborhood.

Back in 2010, nine years before she took charge of the Firkus case, Investigator Nichole Sipes of the St. Paul Police Department was a patrol cop who worked this neighborhood. Jamie Yuccas : Do you remember first hearing about the Firkus case? Sgt.

Nichole Sipes : I do. NICK FIRKUS (to 911): Ahh, please, please, somebody just broke in our house and shot me and my wife. 911 OPERATOR: OK .

.. It was early on a Sunday morning.

Sgt. Nichole Sipes : The 911 call was at 6:30. Nick Firkus' story of a burglar didn't make sense to Sipes.

Sgt. Nichole Sipes : Most people are home at 6:30 on a Sunday morning, especially in a family neighborhood like that. .

.. the last thing that most burglars want to encounter are people.

Jamie Yuccas: Did police ever have any luck tracking down the intruder that Nic.