GRAND RAPIDS, Mich. (WOOD) — It was a murder that haunted West Michigan for more than 13 years.

Renee Pagel, a Rockford-area mother, nurse practitioner and teacher, was stabbed to death in her bed in 2006. For years, authorities thought her estranged husband Mike Pagel had done it — but they couldn’t prove it.

Then, last year, a break in the case: Mike Pagel’s brother told Kent County investigators Mike Pagel had confessed to murdering his wife. He pointed them toward the Saginaw County creek where he said his brother ditched the murder weapon.

Crews went looking. And, stunningly, they dredged up the knife that they say killed Renee Pagel.

On Friday night, “Dateline NBC” profiles the case, speaking to investigators who for years tried to get the evidence they needed to put Mike Pagel behind bars. For the first time, you will hear directly from one of the Pagels’ children, who grew up in her father’s home after her mother’s death.

Target 8 investigator Susan Samples, who has been covering the homicide since it happened, will also appear in the episode, discussing the effect Renee Pagel’s death had on her community and her friends’ commitment to see justice done.

You can watch “Dateline: Window of Opportunity” at 9 p.m. on WOOD TV8.