Harvard University professor of mathematics and biology Martin Nowak has been barred from participating in new research or advising students for a minimum of two years, the university announced Thursday.

The disciplinary action stems from Nowak’s close ties to convicted sex offender Jeffrey Epstein, the Associated Press (AP) reports.

Nowak was placed on paid leave following a May 2020 review that found he violated Harvard’s security protocol by granting Epstein far-reaching access to the school, including a private office on campus and a key card. Nowak allowed Epstein to continue visiting even after his 2008 sex crimes conviction.

Epstein frequented the campus nearly four dozen times after his conviction, most recently in 2018. Visits only stopped when other researchers complained.

Nowak dedicated a page to Epstein on his research centre’s website and linked to his personal webpages, requests granted as favours to Epstein’s publicist, the report found.

Though he had no formal connection to Harvard, Epstein donated $6.5 million to kickstart the professor’s Program for Evolutionary Dynamics, AP says.

Harvard will allow Nowak to continue teaching during the two-year sanction period, but additional contact with students will be limited. In a memo, Claudine Gay, dean of Harvard’s Faculty of Arts and Sciences, says his research center is being shut down “as soon as it is feasible.”

In total, the review found Epstein donated about $9.1 million to Harvard in the years leading up to his conviction. He was barred from making additional contributions after that.

The school’s senior leaders have been cleared of any misconduct. While most of the donated funds had been spent by the time the review was conducted, the remaining $200,000 were distributed to groups that support sex trafficking and assault. 

In a Friday statement, Nowak said he “regrets” fostering a connection between Harvard and Jeffrey Epstein “and the hurt it caused.”

 “I will take the lessons from this time with me as I move forward,” he added.