Police are currently searching the harbor in Portland, Maine for Nathan G. Bihlmaier, an MBA student at the Harvard Business School set to graduate on Thursday.

Business School spokesperson Brian Kenny said Bihlmaier was in Portland with two friends to celebrate their impending graduation.

Bihlmaier went missing Saturday evening after being asked to leave Ri Ra Irish Pub, a waterfront pub near the Maine State Pier, for being visibly intoxicated, according to the Associated Press.

Authorities have been searching for him since Sunday morning.

Portland Police Chief Michael Sauschuck told the Associated Press that divers are searching harbor waters near where Bihlmaier was last seen, using a sonar to aid their search.

Monday afternoon, police reported that they had found an article of clothing near the State Pier. Kenny said while it is unclear whether the article of clothing belongs to Bihlmaier, investigators were “focusing their search” on where it was found.

The police intend to renew their search efforts on Tuesday.

Kenny said several students and family members had come to Portland to join the search and comfort Bihlmaier’s wife, who is currently pregnant with the couple’s first child. Business School Dean Nitin Nohria, Associate Dean Youngme E. Moon, and a number of other administrators were among those who traveled from Cambridge to Portland Monday to help with the search effort.

The graduate school hosted a prayer service on Bihlmaier’s behalf Monday afternoon, Business School spokesman James E. Aisner ’68 wrote in an email.

“Needless to say, everyone in this community is very concerned,” Aisner wrote. “We are all hoping and praying for the best.”

—Staff writer Hana N. Rouse can be reached at hrouse@college.harvard.edu.