Three complaints have been made by Colin Harvey, a professor of human rights law in the School of Law at QUB, about multiple social media posts in February, June and earlier this month.
PSNI Superintendent Gerard Pollock said the complaints relate to “social media comments directed towards an individual”.
“An investigation has commenced to establish if any offences have been committed and enquiries are continuing,” he said in a statement.
Professor Harvey, a fellow of the Senator George J Mitchell Institute for Global Peace, Security and Justice and an Associate Fellow of the Institute of Irish Studies, has been repeatedly criticised on social media for expressing his views on constitutional matters, Brexit, the Protocol, the Conservative Party and unionism.
He has regularly tweeted about social issues affecting a post-Troubles Northern Ireland, his favourable view of a united Ireland and his criticisms of loyalism and unionist leadership.
The Sunday Worldhas viewed dozens of tweets directed at him by mostly anonymous social media accounts claiming to be from a British, loyalist or former security forces background.
When Prof Harvey suggested it “was time” to bring the Union “to an end”, a Twitter user replied: “We used to behead traitors like this.” Another wrote: “Colin Harvey should be called off.”
Outspoken loyalist Jamie Bryson, who has connections to the Ulster Volunteer Force (UVF), has tweeted about Prof Harvey almost 50 times.
When the academic wrote: “The Irish government needs to take direct responsibility for enabling the collective effort of preparing for the future of a shared island,” Mr Bryson, a regular commentator on some BBC Northern Ireland programmes, was quick to respond.
In a tweet, he wrote: “QUB making pretty clear they have moved beyond policy and research and are now partisan activists.”
Prof Harvey said the online abuse he has faced “often feels like a coordinated campaign” and appears to be closely linked to his academic work and public engagement on questions around the constitutional future, in particular the option of a united Ireland.
“At times I struggle to understand why I have become the target for so much anger, and its intensity is concerning. If you really believe in the ‘principle of consent’ then this is an anticipated choice, and you should not be surprised that people like me want proper planning, and even have a view on the outcome,” he said.
He said constitutional objectives “are supposed to be equally legitimate” and should be “uncontroversial work”.
“It is my strong view that everything I have done is anchored comfortably within the framework of the Good Friday Agreement and its good faith implementation. In a post-Brexit environment, it would be irresponsible not to do the required preparation.
He believes the “targeted campaign of harassment” is aimed at attempting to “derail these efforts”.
“That’s not happening, people are pressing on. They are right to do so. And that determination sends its own message.”
A representative from the QUB leadership team has been in ongoing contact with Prof Harvey.
In a statement, a QUB spokesperson said: “Queen’s outright condemns any abusive or threatening commentary towards any member of university staff.
“The university strongly supports freedom of thought and expression within a framework of respect for the rights of other persons. Academic freedom is enshrined as a guiding principle in the university’s charter and statutes.”
Amnesty International said Prof Harvey has been subjected to years-long intimidation by elected politicians, media commentators and online activists.
Patrick Corrigan, Amnesty’s Northern Ireland Director, said the organisation is “deeply concerned at this campaign of sustained hostility against Prof Harvey”.