By . Daily Mail Reporter . PUBLISHED: . 14:47 EST, 21 May 2012 . | . UPDATED: . 07:54 EST, 22 May 2012 . Police in Portland, Maine are looking for a Harvard Business School student who disappeared while celebrating his upcoming graduation. Nathan Bihlmaier, 31, was last seen by the Portland waterfront at Ri Ra, an Irish pub, around one o'clock Sunday morning. After scouring the marina, police still have no clues as to his whereabouts, causing his pregnant wife Nancy to rush to the coastal town. A piece of Mr Bihlmaier's clothing was found in the bay, and police say they are concerned about how close he was to the water when he was last seen after a night of heavy drinking. Vanished: Harvard student Nathan Bihlmaier, 31, was last seen by the Portland waterfront late on Saturday night. He is pictured with his wife, Nancy . Last seen: He and two friends had visited the Old Port area before Mr Bihlmaier vanished around 1am . Police told the Portland Press Herald that Mr Bihlmaier and two friends traveled to Portland for the weekend to celebrate their graduation from business school. The revelers visited the Old Port area on Saturday night, before Mr Bihlmaier was asked to leave the bar soon after midnight because he was drunk. Police confirmed that he had 'a little bit too much to drink', but added that he did not cause a disturbance while leaving the bar. 'At that point he left the bar very cooperatively,' police chief Michael Sauschuck said, according to the Bangor Daily News. 'There were no altercations - he just left voluntarily after being spoken to by bar staff.' He spoke to his friends on the phone, but did not return to the hotel where they were staying. They searched for him to no avail and reported him missing at 9am. Concerned: His pregnant wife, Nancy Hi Bihlmaier, rushed to the coastal city after receiving the news . 'He is a well-established individual from a strong family. He has a wife who is expecting their first child. There is no reason he would [purposely] go missing,' Lt Gary Hutcheson told the Press Herald. 'It's an unusual one.' According to his cell phone records, Mr Bihlmaier did not venture far. Police tracked his movements through his phone signal after he left the bar until his battery apparently died 40 minutes later. Divers scoured the marina, looking for clues to Mr Bihlmaier's location. Family: Mr Bihlmaier, originally from Kansas, with his wife Nancy and his parents Cheryl and Steve . The Coast Guard and the Portland harbormaster worked together with police to launch the underwater hunt for clues. They even used a cadaver dog on an inflatable raft to search for the man's scent. On Monday afternoon they found an item of his clothing in Casco Bay not far from the bar where he was drinking. Mr Sauschuck said: 'We do have some divers in the water, and that concern is really just to look at all options. 'It’s certainly a possibility that Nate could be lost in our fair city, or maybe 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.' Mystery: Police tracked him after he left Ri Ra, pictured, until his phone battery died 40 minutes later . His pregnant wife, Nancy Hi Bihlmaier, rushed to the coastal city after receiving the news that her husband was missing, as did around 20 of his business school friends. Mr Bihlmaier is due to graduate from Harvard Business School this Thursday. 'He is from a strong family. His wife is expecting their first child. There is no reason he would go missing.'Lt Gary Hutcheson . A spokesman for the school told the Press Herald: 'His friends describe him as really one top-notch guy.' He continued: 'We do remain hopeful, despite signs to the contrary. It's important if anybody saw him, we want to hear about it.' Mr Bihlmaier, whose family comes from Kansas but who is now based in the Boston area, specialises in the business of healthcare, and is employed by medical provider Optum. He has previously worked at several other healthcare firms, as well as for the Department of Health and Human Services.
Nathan Bihlmaier, 31, was celebrating graduation at Irish pub when he was asked to leave for being too drunk .
Piece of his clothing found in marina but still no sign of missing man .
Pregnant wife Nancy has rushed to Maine town where he disappeared .
Business school friends describe him as 'one top-notch guy'
By . Daily Mail Reporter . PUBLISHED: . 14:47 EST, 21 May 2012 . | . UPDATED: . 07:54 EST, 22 May 2012 . Police in Portland, Maine are looking for a Harvard Business School student who disappeared while celebrating his upcoming graduation. Nathan Bihlmaier, 31, was last seen by the Portland waterfront at Ri Ra, an Irish pub, around one o'clock Sunday morning. After scouring the marina, police still have no clues as to his whereabouts, causing his pregnant wife Nancy to rush to the coastal town. A piece of Mr Bihlmaier's clothing was found in the bay, and police say they are concerned about how close he was to the water when he was last seen after a night of heavy drinking. Vanished: Harvard student Nathan Bihlmaier, 31, was last seen by the Portland waterfront late on Saturday night. He is pictured with his wife, Nancy . Last seen: He and two friends had visited the Old Port area before Mr Bihlmaier vanished around 1am . Police told the Portland Press Herald that Mr Bihlmaier and two friends traveled to Portland for the weekend to celebrate their graduation from business school. The revelers visited the Old Port area on Saturday night, before Mr Bihlmaier was asked to leave the bar soon after midnight because he was drunk. Police confirmed that he had 'a little bit too much to drink', but added that he did not cause a disturbance while leaving the bar. 'At that point he left the bar very cooperatively,' police chief Michael Sauschuck said, according to the Bangor Daily News. 'There were no altercations - he just left voluntarily after being spoken to by bar staff.' He spoke to his friends on the phone, but did not return to the hotel where they were staying. They searched for him to no avail and reported him missing at 9am. Concerned: His pregnant wife, Nancy Hi Bihlmaier, rushed to the coastal city after receiving the news . 'He is a well-established individual from a strong family. He has a wife who is expecting their first child. There is no reason he would [purposely] go missing,' Lt Gary Hutcheson told the Press Herald. 'It's an unusual one.' According to his cell phone records, Mr Bihlmaier did not venture far. Police tracked his movements through his phone signal after he left the bar until his battery apparently died 40 minutes later. Divers scoured the marina, looking for clues to Mr Bihlmaier's location. Family: Mr Bihlmaier, originally from Kansas, with his wife Nancy and his parents Cheryl and Steve . The Coast Guard and the Portland harbormaster worked together with police to launch the underwater hunt for clues. They even used a cadaver dog on an inflatable raft to search for the man's scent. On Monday afternoon they found an item of his clothing in Casco Bay not far from the bar where he was drinking. Mr Sauschuck said: 'We do have some divers in the water, and that concern is really just to look at all options. 'It’s certainly a possibility that Nate could be lost in our fair city, or maybe 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.' Mystery: Police tracked him after he left Ri Ra, pictured, until his phone battery died 40 minutes later . His pregnant wife, Nancy Hi Bihlmaier, rushed to the coastal city after receiving the news that her husband was missing, as did around 20 of his business school friends. Mr Bihlmaier is due to graduate from Harvard Business School this Thursday. 'He is from a strong family. His wife is expecting their first child. There is no reason he would go missing.'Lt Gary Hutcheson . A spokesman for the school told the Press Herald: 'His friends describe him as really one top-notch guy.' He continued: 'We do remain hopeful, despite signs to the contrary. It's important if anybody saw him, we want to hear about it.' Mr Bihlmaier, whose family comes from Kansas but who is now based in the Boston area, specialises in the business of healthcare, and is employed by medical provider Optum. He has previously worked at several other healthcare firms, as well as for the Department of Health and Human Services.
while celebrating his upcoming graduation. Nathan waterfront at Ri Ra, an Irish pub, around one Bihlmaier's clothing was found in the bay, and student Nathan Bihlmaier, 31, was last seen by was asked to leave the bar soon after midnight for him to no avail and reported him missing at waterfront to where he was last seen.' Mystery: His pregnant wife, Nancy Hi Bihlmaier, rushed to 'His friends describe him as really one top-notch