It's been nearly four decades since Cheryl Lynn Springfield was found beaten and strangled on Christmas Day 1980.
Circumstances surrounding her death and unanswered questions have tormented the woman's sister, Jan Tunnell Webster, since that day.
"I stood over her casket, and I put my hand over hers, and her little fingers were wrinkled and I promised her I will find out who did this," said Webster.
She vowed she'd never break that promise after her only sister was murdered.
Springfield was just 21 years old when she was found dead inside a quaint home on Whittier Street in Fort Worth.
She had her whole life ahead of her. The spunky, happy brunette had been working things out with her ex-husband, Scott. The two had planned to spend Christmas together with their young son, but instead, her ex-husband – who was ruled out as a suspect – found her body.
Springfield was naked and bloody next to the Christmas tree. Detectives say she was strangled with a cord that was still tightly wound around her neck.
"It was brutal, and I mean it takes a lot to look into someone's eyes and watch the light go out," said Webster.
A neighbor on Whittier Street told detectives they saw Springfield speaking with someone outside the home in the early morning hours that Christmas day. The witness, however, couldn't give a good description of the person.
Fort Worth police were able to lift a partial fingerprint as well as DNA from the scene. All these years later, though, there has still been no match.
Webster believes it's only a matter of time.
"We may not be able to get it now, but technology will catch up. And if you're 80 years old and I have to come jerk you out of the nursing home, I intend to do that," Webster said, of her sister's killer.
It's a personal crusade Webster has been on for 36 years.
"I will never give up," she said.
Fort Worth police are actively investigating Springfield's case. Anyone with information is asked to call the FWPD Cold Case Unit at 817-392-4307.