48 Hours: Did an online map lead a killer to the wrong house?

Dennis Koula (left) and his wife, Merna
Dennis Koula (left) and his wife, Merna

(CBS) -- As a producer for 48 Hours, I've spent years attending murder trials. If you're reading this, you're probably a fan of the show so you already know that we often come across cases with interesting twists. Well, I covered a trial this past summer in La Crosse, Wis. that had one of the most unusual twists I'd heard in a while.

Dennis and Merna Koula, both in their sixties, were enjoying semi-retirement in May 2010. Living comfortably in a four-bedroom home that backed up to a golf course, they had two grown children and several grandchildren who lived minutes away.

On May 24, 2010, their son Eric headed over to the house to check on them. Alerted by a school secretary that his mom hadn't shown up to substitute teach that morning, what Eric found when he entered his parents' home was devastating. Dennis and Merna had been killed, each shot once in the head execution-style.

Local authorities were perplexed. Who would want to kill these two beloved grandparents? A few days later, investigators caught their first break. Steve Burgess, a bank president who lived just two houses away, came forward to say that he'd been receiving death threats at his home - scary phone calls saying his "days were numbered." He was concerned that somehow the Koulas had been killed instead of him - a case of fatal mistaken identity.

And here's the strangest twist of all - it turns out that when you enter Steve Burgess' address into Google Maps...the map's arrow flies down to the foot of the driveway...of the Koula house!

In a rural area like this, it's very common for technology to come up a bit short. In the course of my own reporting on the story, the GPS in my rental car gave up about a half mile away from the Koula house. Could an online glitch have led to a double murder?

To find out, watch 48 Hours: Desperate Measures, Saturday, Feb. 9, at 10p.m. ET/PT.

This story was written by 48 Hours producer Susan Mallie