Don Rentz, 84, and his wife Reda, 80, were last seen alive in late February. Their bodies were found March 7, 2015, when their children couldn't contact them.
"It's like a cloud that's always around," said their daughter Judith Crane. "Not always in the forefront, but it's always there."
Crane and her sister live in the San Antonio area. Their parents, according to neighbors, were planning to move there to be closer to their children.
According to sheriff's homicide detectives at the time, the back door of the home was unlocked. It's unknown if the killer was someone the couple knew, or burglars looking for an easy target. The cause of death was listed as blunt force trauma. Things inside their home had been disturbed, and drawers were open.
"They took some things of no consequence," said Judith Crane. "And my parents were so frail."
Don and Reda Rentz were fixtures in the neighborhood, their church and their community, where they volunteered to serve the needy.
"They were well-liked," said one neighbor. "We'd always see them walking in the afternoon."
Don and Reda were married for nearly 60 years at the time of their deaths.
There were some leads in the case, but no arrests.
"I believe that if there was some real information, then there would have been," said their daughter.
"I know someone knows the person who did this," she said, "and I know they are probably too scared to come forward."
"But it's better to do the right thing and be able to move on with your life. And I'm sure if you're withholding this kind of information, it's hard to move on as well."
The $20,000 reward stands for any information that solves the brutal homicides of Don and Reda Rentz. The information can be phoned in to Houston Crime Stoppers at 713-222-TIPS, or on their website at www.crimestoppers.org. All information given is anonymous.
The legacy of the couple to their children included their faith.
"I know God will deliver justice," said Judith Crane. "I hope it will be in my lifetime."