A Minnesota cold case solved: The murder of Heidi Firkus featured on ABC's 20/20
Nicholas Firkus was sentenced in April for the murder of his first wife. The episode, 'Stranger in the House,' can be viewed now on Hulu.
The 2010 death of 25-year-old Heidi Firkus was considered one of Minnesota's most infamous cold cases — until one group of investigators years later honed in on her husband, Nicholas Firkus.
Nicholas Firkus was convicted in February 2023 on first-degree murder charges. In April, a judge sentenced him to life in prison without parole.
Nicholas Firkus initially told investigators his wife died after an unknown man broke into their St. Paul home. He claimed a struggle ensued, causing him to release the grip on the gun he was holding.
Nicholas Firkus claimed the assailant took hold of the gun, and fired it at his wife, resulting in her death.
The alleged killer was never caught — until investigators turned their attention toward Nicholas Firkus.
Following Heidi Firkus' death, her husband remarried and had three children. His second wife was the first to suspect that he could have been responsible for the death of Heidi.
As her suspicions grew, she began recording her husband. Those recordings were critical in the case against him.
Nicholas Firkus had gotten into financial trouble during his marriage to Heidi, resulting in the foreclosure of their home. He told investigators that Heidi was aware of their financial struggles, and they planned on moving out together.
He played the role of a heartbroken — and confused — husband.
But, that wasn't the case. Instead, prosecutors uncovered the reality: that he had kept his wife in the dark, and killed her before she was able to find out about their financial woes.
The sentencing is bringing more awareness to this Minnesota cold case, which was featured on 20/20 in April 2023. That episode, "Stranger in the House," can be viewed now on Hulu .