ALBANY — Karen Wilson would have turned 50 years old on Feb. 10.

"We shed some tears that day. She's never been out of our thoughts," said her mother, Jennie Wilson.

Her 22-year-old daughter, a University at Albany senior and a state Assembly intern, vanished from the campus on the evening of March 27, 1985, a Wednesday. Karen had shopped for T-shirts and shorts at Colonie Center, finished a session at the Tanning Hut on Central Avenue and then walked along Fuller Road to campus. She was getting ready for a spring break trip to Fort Lauderdale with her dormitory roommate.

She was dressed in blue jeans, a light blue polo shirt, a cream-colored raincoat and sneakers. She was wearing a Zircon ring and a Seiko watch with a black face and she carried a gray cloth pocketbook.

Her disappearance spawned one of the longest and most intensive criminal investigations in Capital Region history. The passage of time and the extraordinary resources employed by law enforcement agencies have failed to crack the case.

There is no suspect. There are no witnesses. There is no crime scene or physical evidence and no body was ever recovered. It's as if Wilson's case has been suspended in time since 1985.

But from time to time a random event, such as the fatal fire in Glenmont on Feb. 20 that left 61-year-old Brad Woodworth dead from smoke inhalation, will thrust the Wilson case back into the public consciousness. State Police, who continue to investigate Wilson's disappearance, confirmed that Woodworth was interviewed by investigators in 1985 as a person of interest in the case.

A fresh twinge of anguish for Wilson's parents, who live in Utah, was also a grim reminder for retired UAlbany Police Chief James Williams.

"I think about it every day and never stopped going over the case in my mind," said Williams, 72, of Delmar, who retired in 1996 after 26 years with the campus police. "We followed every lead we got, more than 2,000 of them. We interviewed hundreds of people. Frankly, I can't think of anything we did wrong."

There has never been a significant break in the case. "The guy who did this did it alone and didn't talk. Ever," Williams said. "He didn't get drunk and brag in a bar. We never had a strong suspect in 28 years, and we still don't."

After he retired, Williams took three large boxes of files to his home and pored over their contents for years. He finally turned them over to State Police Senior Investigator David Madden, head of Troop G's Major Crimes Unit.

Confirmed sightings of Wilson ended in the Colonial Quad parking lot between 7:30 and 8 p.m. Investigators believe Wilson, 5 foot 3 and 115 pounds, was snatched in the dorm parking lot by a lone man in a car.

They were not able to develop any sort of suspect portrait. "There was nothing to profile," Williams said.

To test the theory that seemed most plausible, a large male trooper grabbed a petite female trooper, pushed her into a car trunk, closed the lid and drove away during a re-creation of an abduction scenario in the parking lot of the State Police Academy. They checked a stopwatch.

"It took 10 seconds," Williams said.

Woodworth, who was a 33-year-old truck driver living along Hilton Road in rural Voorheesville in 1985, became a person of interest several months into the investigation after an anonymous caller gave authorities Woodworth's address and told detectives to investigate him.

"We worked on Woodworth for a couple years," Williams said. "We had already run all the local convicted sex fiends and he wasn't in that group. It was such a strange and specific tip that we pursued it."

Williams said Woodworth's alibi checked out after his boss vouched that he arrived for his shift at 4 a.m. as usual on March 28, 1985. "If he did take Karen the night before at 8 p.m., it just didn't seem possible that he'd report to work at 4 a.m. the next morning," Williams said. Interest in Woodworth faded.

That interest was revived about a year later when another anonymous caller told investigators to look for Wilson's body in a wooded area near the abandoned Tall Timbers Country Club off Maple Road — close to Woodworth's house on Hilton Road.

"I searched those woods for three months without any success," Williams said. He brought in Andy Rebmann, a Connecticut State Police investigator and cadaver search dog specialist. Rebmann and his trained dogs spent a day traversing the woods without finding anything.

"It went nowhere," Williams said.

Interest in Woodworth receded once more. His name did not come up again until he died in the Glenmont Road house fire on Feb. 20 and Bethlehem Police, aware that Woodworth was questioned about Wilson, called State Police.

Williams and Madden got word to Wilson's parents.

"As far as we know, nothing connects him to our daughter's disappearance. We're sorry this tragedy happened to him and pulled his name back up," Jennie Wilson said. She and her husband, Taylor, a retired Air Force pilot and lieutenant colonel, were stationed at the former base in Plattsburgh when their daughter disappeared.

They are grateful that Williams and Madden keep in touch and inform them any time a shred of new information arises. "It's an open case and we still work on it," Madden said. "We utilize national resources. When a tip comes in, we follow it up. We never say never."

The family has learned to temper its hopes. "Each time something like this (Woodworth's death) comes up, it goes away and nothing changes," Jennie Wilson said. "We don't know anything more today than we did in 1985."

pgrondahl@timesunion.com • 518-454-5623 • @PaulGrondahl