A MINNESOTA WIFE SHOT AND KILLED IN HER HOME - A 911 CALL AND AN EAR WITNESS TELL THE STORY OF A BURGLARY, BUT EVIDENCE AT THE SCENE POINTS TO A DIFFERENT KILLER

"48 Hours" Reports in "Death at the Front Door: Who Shot Heidi Firkus?"

At 6:30 in the morning of April 25, 2010, Heidi Firkus called 911 after her husband, Nick Firkus, said an intruder was breaking into their home. She was shot and killed and Nick Firkus told investigators that his gun discharged when he struggled with the intruder. Minnesota-born correspondent Jamie Yuccas reports on the investigation in 48 HOURS: "Death at the Front Door: Who Shot Heidi Firkus?" to be broadcast Saturday, Dec. 2 (10:00-11:00 PM, ET/PT) on the CBS Television Network, and streaming on Paramount+.

Something in Nick Firkus' story struck police as odd.

"Most people are home at 6:30 on a Sunday morning, especially in a family neighborhood like that," detective Nichole Sipes of the St. Paul Police Department tells Yuccas. "The last thing that most burglars want to encounter are people."

In his first network TV interview, Branden O'Connor, who was housesitting and taking care of kittens next door to the Firkus residence, recalls hearing something strange.

"I was woken up by the kittens kinda walking around," O'Connor tells Yuccas. "Some noise got my attention, so I stuck my head out the window."

Branden recalls hearing a muffled argument coming from the Firkus home.

"That's when I ended up hearing what sounded like gunshots," he tells Yuccas.

When first interviewed by police, O'Connor said he also heard a male voice. "Kind of this agonizing yell of, 'You shot her, you shot me ... please, please, no,' something along those lines and then - then it was done. You know, I'm looking, I didn't see anybody come out the house," he says.

Sergeant Jim Gray breaks down the scene for 48 HOURS. He says the evidence at the scene didn't match Nick Firkus' accounts.

"They have this life and death struggle right in this area with nothing disturbed," Gray says.

Gray also tells Yuccas that by the front door where the alleged struggle occurred there was a vase, some receipts, a beer bottle and none of that was knocked over. "So that kind of raised suspicion to us that if there was such a struggle, why wasn't any of this stuff knocked over?" Gray says. "His story didn't make a lot of sense to me ... His version of the incident couldn't be plausible."

Nick Firkus went free for more than a decade until investigator Nicole Sipes took over the case. As part of the new investigation, Sipes reached out to Nick Firkus' new wife who gave her a recording that ultimately led to Firkus' arrest.

48 HOURS is broadcast Saturdays at 10:00 PM, ET/PT on CBS, and streams anytime on Paramount+. You can also watch 48 HOURS on the CBS News Streaming Network Wednesdays at 8:00 PM, ET. 48 HOURS is also available on CBSNews.com, Fave TV, Pop TV, Pluto US, Pluto UK, Pluto Nordics, Pluto Canada and Pluto South Africa. Download the CBS News app on your phone or connected TV. Follow 48 HOURS on Twitter, Facebook and Instagram. Listen to podcasts at CBS Audio.