Family and friends are mourning the death of an expectant father who was scheduled to graduate from Harvard Business School on Thursday.

The body of Nathan Bihlmaier, 31, was recovered from Portland Harbor on Tuesday, two days after he disappeared from Portland’s Old Port. An autopsy by the state medical examiner is anticipated today, but police say they have no reason to suspect a crime.

The dean of Harvard Business School, Nithin Nohria, traveled to Portland to offer support to the family.

“It’s a tragic moment for our community. We’re a tight-knit school,” he said at a news conference alongside Ri Ra Irish Pub, the last place Bihlmaier was seen.

“Nathan was an outstanding member of our community,” he said. “He was highly regarded by his friends as a gregarious person.”

Bihlmaier and two friends had come to Portland’s Old Port night life district to celebrate their pending graduation. Staff at Ri Ra Irish Pub told Bihlmaier to leave at 11:20 p.m. because he had too much to drink, at which point he became separated from his friends, said Portland Police Chief Michael Sauschuck.

Police reviewed security video from Ri Ra and confirmed the timing of Bihlmaier’s ejection.

The friends and Bihlmaier exchanged telephone calls as they tried to rendezvous, but they could not find each other. Bihlmaier, who was from Kansas and unfamiliar with Portland, told them he was in front of a building resembling a state capitol, which police surmise was U.S. Custom House, an ornate grey edifice on Commercial Street.

Bihlmaier told his friends he was OK. The last telephone conversation was at 12:15 a.m.

Cellphone location information shows the last known location of Bihlmaier’s cellphone to be in the area of the Maine State Pier at 12:54 a.m. Sunday. At that point, his cellphone went dead, though police do not know if it ran out of battery or became submerged.

Staff members of Sen. Olympia Snowe and Rep. Chellie Pingree, D-1st District, attended Tuesday’s news conference and have been following the search closely.

Snowe was asked to be a point of contact for information by former Sens. Bill Frist, R-Tenn. and Judd Gregg, R-N.H., who both have sons who are close friends of Bihlmaier’s and who attended Harvard Business School. Harrison Frist is scheduled to graduate Thursday in Bihlmaier’s class.

Pingree also was asked to monitor the search and she, too, has connections to the business school. Her step-daughter Carolyn Tisch Sussman is graduating from the business school Thursday and Pingree plans to attend. Sussman, whose father S. Donald Sussman, owns a controlling stake in the company that publishes the Portland Press Herald, Kennebec Journal and Morning Sentinel, knew Bihlmaier, although they were not close, a spokesman for Pingree’s office said.

Both officials extended their condolences to the Bihlmaier family.

Sauschuck said the magnitude and intensity of the search was not related to Bihlmaier’s connections.

“Whenever we have a missing persons case no matter what the circumstances are we try to get to the bottom of the situation as quickly as we can both for the individual and for the family involved,” Sauschuck said.

Eighteen officers from Portland, South Portland and Maine State Police wearing scuba gear dove in the murky water around the piers and pilings of Portland’s waterfront, searching the debris-strewn bottom.

Police dragged a side-scan sonar apparatus to get a picture of the harbor bottom to help focus the search, and Maine Search and Rescue used dogs able to detect the smells given off by a body underwater. But ultimately it was a State Police diver searching a grid pattern that made the discovery.

Bihlmaier’s body was found at 11:45 a.m. in deep water off Custom House Wharf by a Maine State Police diver.

Police identified Bihlmaier by his clothing — a black V-neck sweater, blue pants and a gray T-shirt — which witnesses and security cameras confirmed he was wearing when he was last seen early Sunday morning in the Old Port. Police on Sunday afternoon found one of Bihlmaier’s flip-flops in the water alongside Maine Wharf, just south of Maine State Pier.

Bihlmaier’s wife, Nancy, came to Portland as the search got under way, as did his parents, Steve and Cheryl, who arrived from Kansas. More than a dozen classmates from Harvard Business School also gathered. Bihlmaier’s mother told the Boston Herald that he had planned to surprise his parents at the graduation with news that Nancy was pregnant.

They were told of Tuesday’s recovery by Sauschuck.

Brian Kenny, a spokesman for Harvard Business School who has spoken on behalf of the family during this ordeal, said the family was “very upset, stressed.”

“I think we were all holding out hope he was alive,” Kenny said. Friends declined comment.

Nohria said that graduation from Harvard Business School is a dream for many individuals and their families and should be a time of joy, but now the celebration will be tinged with sadness.

Sauschuck said Bihlmaier’s death does not suggest Portland is a dangerous place.

“The city of Portland is an incredibly safe place to live,” he said. “Things do happen in the Old Port as they do anywhere else.”

Sauschuck said it would be nice if a bar did some follow up when somebody has been told to leave for being too intoxicated, to make sure they have a way to get home or have friends who can look after them, but he said the workers at Ri Ra do not appear to have committed any infractions, though police will continue to investigate the circumstances leading up to Bihlmaier’s death.

Police plan to review additional video taken from businesses in the area to try to determine how Bihlmaier came to be in the water. So far, none of the video they have seen shows him besides the one from Ri Ra, Sauschuck said.