BY DAVID HENCH

The Portland Press Herald

Portland police continued a grim search for a missing Harvard Business School graduate last seen near the waterfront of the city’s Old Port nightlife district.

Nathan Bihlmaier, 31, whose wife is pregnant with their first child, was in town with a couple friends to celebrate their graduation from the Cambridge business school set for Thursday. The three were in Ri Ra Irish Pub late Saturday night when Bihlmaier was told to leave because he had had too much to drink, police said.

Police on Sunday found an article of clothing they believe belonged to Bihlmaier in water just south of the Maine State Pier, though they would not describe the item. There was no indication Bihlmaier was a victim of foul play.

Police Monday were canvassing businesses in the area to retrieve security video that might show Bihlmaier after he left the bar, which overlooks the harbor, said Portland Police Chief Michael Sauschuck.

Bihlmaier became separated from his friends and communicated a few times with them by cellphone before 1 a.m. when police say the phone stopped working. In one of those final phone calls, Bihlmaier described a building on Commercial Street that he was in front of, in an attempt to rendezvous with his friends.

However, they did not see him again that night and when he had not returned to the Hilton Garden Inn, where they were staying, by 9 a.m. Sunday, they called police.

Sauschuk Monday said it’s possible Bihlmaier could be lost in the city or caught a ride somewhere. “But given the information we have at hand, we are concerned with the proximity of the waterfront to where he was last seen and so we are looking with the dive team,” he said at a news conference on the waterfront.

Divers from Portland and South Portland police spent several hours Monday searching around the piers and pilings of the waterfront, and used a search and rescue dog with a keen sense of smell positioned on the bow of a rigid inflatable boat. The Maine State Police was expected to bring side-scan sonar apparatus, which can generate an image of the ocean bottom, enabling authorities to search farther into the bay, Sauschuck said.

“Obviously, this is something we have a full court press on,” he said. “We have a great deal of resources involved in this and will continue until we’re able to bring some answers home to the family.”

“It’s a very traumatic time for the family, I have had the opportunity to meet his parents as well as Nate’s wife and they’re doing the best they can given the circumstances,” Sauschuck said. “It’s a scary time for everybody. They’re very strong, caring folks.”

A representative from Sen. Olympia Snowe’s office attended the briefing and said that some colleagues of Snowe in the Senate had asked her to keep them informed about the search. Some children of U.S. senators are fellow students at the top-flight business school, said Cheryl Leeman, who also is a Portland city councilor.

Family members and many of his fellow Harvard Business School classmates kept a vigil Monday as they waited for news about the search.

Brian Kenny, a spokesman for Harvard Business School, said Bihlmaier is a popular student and some 18 to 20 fellow students had driven up to Portland to offer support to his wife and parents. The school will graduate about 900 students on Thursday.

“His friends describe him as really one top notch guy,” Kenny said.

Bihlmaier had already started working at a health care technology company and was looking forward to graduation, he said.

“I’m told he is really passionate about health care that’s why he chose that for his career,” Kenny said. Family and friends are trying to stay positive, he said.

“We do remain hopeful, despite signs to the contrary,” Kenny said. “It’s important if anybody saw him, we want to hear about it. Any information at all.”