NEW MADRID COUNTY, MO (KFVS) - It's been 19 years since a man with a gun talked his way into Sherry Scherer's Portageville, Missouri home and brutally killed both her and her 12-year-old daughter Megan.
Now, a 20-year-old cold case out of Memphis, Tennessee is breathing new life into the Scherer investigation.
This huge, new lead comes thanks to a DNA match.
In a Heartland Unsolved exclusive, we sat down with investigators facing a new challenge.
If they can solve the Memphis rape case, they've got their killer.
"It was real. It hit us. There's no going back."
We recently sat down with Tony Scherer and his son Steven for a Heartland Unsolved that focused on the 1998 murders of his wife and daughter.
It's the first time they've spoken to us about their sudden, inexplicable loss.
"No bringing anybody back," Scherer said about that tragic day. "No turning the clock back. It was a situation we were going to live with for the rest of our lives."
Now, there's a new lead, from an unsolved case even colder than the Scherer murders.
"It was a 1997 rape out of Memphis, Tennessee."
Missouri Highway Patrol Master Sargent Bud Cooper has been on the Scherer case since day one.
He got the call in early May about the new DNA match.
"It was an unsolved rape and they did not have anyone in custody," he said about the 1997 Memphis case.
Cooper and New Madrid County Captain Chris Hensley immediately headed to Memphis. This case had a living victim and witnesses.
Police came up with a composite sketch that both investigators believe looks similar to the composite drawn after police matched the bullets from the Scherer murders to a shooting just hours later in Dyer County, Tennessee.
"When you look at them, you can certainly tell that those people were trying to draw the same person," Cooper said.
Ballistics match Portageville and Dyer County.
In 2006, it was learned DNA matched the Scherer double murders to the 1990 rape and murder of a 28-year-old woman in Greenville, South Carolina.
Now, DNA links that same killer to the 1997 rape in Memphis.
Two rural crime scenes. Two in much more populated areas. But, Hensley points to a similarity in all four.
"They're all located near an interstate or a major highway," he said.
A serial killer and rapist, unknown to his victims, who in at least three cases did not have to break into their homes.
"The guy talked his way in, used a ruse, to get his foot into the door of the house," Cooper said after reading the Memphis case file.
Both investigators say it now makes sense they found no signs of forced entry at the Scherer house.
"So, it bridged a gap for us," Cooper said about the Memphis case. "Now we had live victims talking and able to tell us what he said, what he was doing, what he was thinking."
"Apparently, he has this down to a routine on how he gains access and what took place inside the residence, which apparently took about the same amount of time," Hensley said.
How much time?
"About 30 minutes at each place."
When asked if one man could do that much damage in just 30 minutes, Hensley said yes.
The Memphis suspect used a revolver to control his victims, the same kind of weapon used to kill Sherry and Megan and the same kind of weapon used in Dyer County.
He allegedly restrained his Memphis victims, just like Sherry and Megan. So now, this 20-year-old case brings new hope.
"When you're working a 19-year-old homicide that means this much to you, the fact that we get another chance is really all that we're looking at," Cooper said. "The fact that there's another opportunity, that we get another shot."
Tony Scherer said he's grown more patient over time as he waits to see if his wife and daughter's killer will ever be identified.
"This guy can't be that lucky. Somebody saw something. Even though it's been 19 years, I've seen stranger things happen."
After 19 years, has his mindset changed?
"I've become more patient," he said.
When asked in what ways, he said, "Well, if it's going to happen, it's going to happen. It hadn't happened yet."
"We want to solve it," Cooper said. "It's been tough on this whole community, the county, the family. I mean, it's one we really need to get solved."
Cooper said they haven't talked to the Memphis victims yet, but hope to soon.
As for the DNA match, it took so long because Memphis police say this rape kit was among thousands that sat untested until the backlog was discovered in 2013.
As mentioned in the report, we are working on a special Heartland Unsolved report on the Scherer case.
In fact, it will be our first half-hour special called "The Hunt for a Serial Killer" and airs this July.
Look for more information on the Memphis lead, and the show, in the weeks to come.