Don Billings was 30-years-old when he disappeared in February 1997. Janice Billings Havens

For the past 19 years, Janice Billings Havens has not been a big fan of Valentine's Day.

"I don't ever celebrate it, really, not since Donald disappeared," Janice told Dateline. "It would be like celebrating my brother's missing date."

Donald Billings, who has been called Don since childhood, was last seen on Valentine's Day 1997. His disappearance has puzzled police in Marion, Virginia for nearly two decades.

"This is a small town,rural area, and things like this don't really happen out here," Sheriff Chip Shuler, of the Smyth County Sheriff's Office, told Dateline. "It's one of those dead-end cases;just every lead has fizzled out." Sheriff Shuler has been looking at the case since 2001.

Don spent the last day he was seen with his brother-in-law, Janice's husband. He then borrowed his sister's vehicle and said he would meet her at the local bowling alley later that evening. The two had a set date every Friday to bowl. He never missedit.

"When he didn't show up, I got suspicious something was wrong," Janice said. However, she says she was told she couldn't report him missing for 48 hours.

It was two days later that Janice was told her vehicle had been in an accident Friday afternoon, just about a half hour after Don left. The car had slid off the road. Another driver told police he stopped to ask if the driver, later identified as Don, was all right. The man said he was fine, then headed down the road on foot.

"He locked the car, took the keys, which is very strange if he was running away," Janice said. "Why wouldn't he have left the keys or something like that? It makes no sense."

Rumors have circulated in the town in the months and years since, some including whispers of drug dealers and a possible hit on Don. Another focused on Don possibly being put into a witness protection program for snitching on a few of his friends, who may have been cooking methamphetamine.

Law enforcement has checked out several of the theories, but none of them has played out.

"I've run him through every database and every resource I have access to," Sheriff Shuler told Dateline. "One theory we have ishe had wandered off into the woods nearby, got lost and died from exposure. We've found others who that has happened to. But you would think we would have found him by now. I just want some answers for his family. It’s been too long without them.”

With the anniversary of her brother's disappearance here once again, Janice hangs on the last time she spoke with him. She says Don wasn't himself that day. "He was out of character," she told Dateline.

"He made a comment about saying how he would never do anything to hurt Mom. They were really close. That was odd. Maybe he knew something was going to happen."

If you have any information regarding Don's disappearance, please contact the Smyth County Sheriff's Office (276) 783-7204.