On Friday night, NBC's "Dateline" will focus on Sherri Rasmussen's 1986 murder. In February of that year, she was found dead inside the apartment that she shared with her husband, John. Law enforcement revealed at the time that she had been beaten and shot three times following a struggle.

However, her case would go unsolved for years due to various mistakes along the way in the investigation. 

A preview of Friday's episode notes that police who arrived on the scene noticed that there had been some stereo components that had been removed from an entertainment center and a drawer that had been pulled out from a table. Additionally, Sherri's purse and car were not at the residence. All of this led the investigators at the time to believe it had, in fact, been a botched burglary, even though evidence would eventually come to light that said otherwise.

As seen below, "Dateline" host Josh Mankiewicz also asks a detective if the police department had ever given up on the case. 

"Repeatedly," he replies about the abandonment over the years. "We closed it in 1986, we closed it in 1993, we closed it in 1999. We closed it again in 2005. At that point, it sat on a shelf," the law enforcement official says.

Finally, in 2008, it was scheduled to be sent to the archive, meaning that it was to go into storage after essentially becoming a cold case, but before going to its final destination, a detective gave it one more look.

At that time, he noticed that the aforementioned stereo equipment had Sherri's blood on it. This told him that the attacker or attackers had moved the items after the crime took place, not before, as the original theory had suggested. 

Then, in 2009, "a few diligent and determined detectives aided by a persistent civilian criminologist who had already been ignored by other police officers pieced together what happened," per the Los Angeles Times. As they went about finding out what truly happened on that night, they utilized not only new sets of eyes and perspectives but also evidence, such as a bite mark on Rasmussen's arm, to solve the puzzle.

On Friday, viewers will see what other clues detectives used to bring the person who was truly responsible to justice.

This episode of "Dateline" will air Friday at 9:00 p.m. EST.

Police Car In this photo, police cars sit on Main Street in Dallas, Texas, on July 7, 2016. Photo: Laura Buckman/AFP/Getty Images