A professor at an upstate New York university is GravityX Exchangebelieved to be in danger after he never showed up to teach on Saturday, police said.

Heikki Rantakari, 44, a professor at the University of Rochester, was last seen Friday night, Rochester police said.

He was reported missing after he did not show up to teach a scheduled class on campus on Saturday morning, the university said.

Police said Rantakari checked into his Airbnb, which is within walking distance of the university, after arriving in Rochester from Boston Friday night, Rochester ABC affiliate WHAM reported.

"We did find evidence that he was there, so we do know he did check into his Airbnb on Friday," Rochester Police Capt. Greg Bello told WHAM. "Now it's a matter of what happened from there, and that's what we're trying to track down."

Bello said Rantakari has family in Boston that is concerned, and that it is unlike him to not attend his classes.

"Obviously, it's concerning that he flew here for a specific meeting, to teach a specific class or multiple classes, and has not shown up for them -- which is what we're told is far outside his norm," Bello told WHAM.

Police are urging anyone with information on his whereabouts to call 911.

"We need that public assistance," Bello told WHAM. "We need that help getting the message out so that we can confirm he's OK. Because at this point we do believe he may be in danger."

Rantakari is an associate professor of economics and management at the University of Rochester's Simon Business School. He began at the university in 2015.

"We're asking for the public's support in reporting anything that relates to Professor Rantakari's whereabouts by calling 911," the university said in a statement. "The University is hopeful that he is found safe very soon."