Authorities announced today that a hospital worker on a smoke break last week may have talked to missing Notre Dame student Chad Sharon hours after friends and witnesses last saw the freshman leave an off-campus party.

The Madison Center Hospital worker told police he was standing outside the building along Niles Avenue about 4 a.m. Dec. 12 when he was approached by a man who fit Sharon's description, said Rex Rakow, director of Notre Dame Security/Police at a news conference this afternoon. The worker said the man asked for directions to a convenience store and he pointed the man south on Niles.

The witness reported that he smelled alcohol on the man's breath but that he didn't appear intoxicated, Rakow said.

A police dog picked up Sharon's scent at the riverbank near the hospital at 403 E. Madison St., Rakow said, but another dog failed to get a scent.

This potential sighting places Sharon about a mile and two hours from the Corby Boulevard party where witnesses last saw him about 2 a.m. Dec. 12.

While Rakow was optimistic about the new lead, he said police still have few clues to solve the week-old disappearance. He acknowledged that authorities' concern increases as time passes but said police have found no evidence suggesting 18-year-old Sharon encountered foul play.

"It's baffling," Rakow said. "We're taking the case day-to-day. As long as Chad isn't found, the case will always be open."

Police today continued their search of the northeast neighborhood. From midnight to 3 a.m., police canvassed the area, passing out flyers at late-night businesses.

Northern Indiana Search and Rescue officials and dogs today also walked routes, including one that stretched from Corby Boulevard to Niles Avenue. Searchers will return to the Niles Avenue area Friday, Rakow said.

Fire officials continued canvassing the St. Joseph River by boat today. An Indiana State Police helicopter was scheduled to fly over neighborhood but couldn't because of rain.

Meanwhile, police renewed their plea for local residents to check their property, especially remote areas on their grounds.

Sharon, of Pelican Lake, Wisc., went missing after he turned down friends' offer of a ride from the Corby Boulevard house party to campus.

He wasn't carrying a cell phone and hasn't contacted friends or family in the past week, police said. He didn't have a car.

Sharon's credit card and bank records show no transactions since his disappearance, Rakow said.

Friends reported Sharon missing to Fisher Hall residence staff on Friday, and hall officials filed a missing-persons report with Notre Dame Security/Police early Saturday.

Sharon had left the hall the previous weekend without telling anyone where he would be, but he returned after one night. He had likely spent the night in another campus residence hall, Rakow said.

Many had hoped Sharon would return early this week, in time for final exams. NDSP alerted news media to the case on Monday and on Tuesday enlisted the help of South Bend police.

On Wednesday, the FBI entered the investigation to examine a link between Sharon's case and the disappearances of four other college-age men and women who, according to The Associated Press, have been reported missing in Minnesota and Wisconsin since late October.

"We have no reason to think there's a connection [between the cases]," University spokesman Matt Storin said in an interview earlier today. "We're just being prudent."

Authorities today entered Sharon into the Center for Missing Children and Adults database. His case had already been announced in a nationwide police bulletin Monday.

School officials announced the disappearance to the campus in an e-mail Tuesday. Since then, police and well-wishers have hung posters around campus.

A Mass for Sharon in the University's Basilica of the Sacred Heart is planned for 5:15 p.m. today.

Contact Jason McFarley at mcfarley.1@nd.edu

• New clue surfaces in disappearance of Notre Dame freshman