In the email, which was reported by The Times, she said: “We do not tolerate any instances of abuse, offensive behaviour, open or covert hostility, directed at others on the grounds of race, religion or belief.”
But Jewish students at the university have criticised the college for not doing more to find the perpetrators.
Harry Hatwell, 26, a student at St John’s, told The Times: “Their response reeks of, ‘This happened, but let’s all move on’.
“The college hasn’t asked, ‘If you know who it was, come forward’.
“The goal is for everything to just go on as normal while the college can reiterate, ‘We’re still inclusive’. And yet the underlying issue isn’t dealt with.”
Another student, from Regent’s Park College, told the newspaper: “It’s taken a massive toll – many fellow Jewish and Israeli students are struggling academically as a result of the atmosphere.”
In response to the criticism, the college said it would be “irresponsible” to give details of its investigation in public.
In a statement, the personal assistant to the principal of the college said: “The college has made it clear that it takes this incident extremely seriously and that it is completely unacceptable.
“It is a distortion of our statement to suggest otherwise. We encourage those who can assist us in identifying those responsible to do so, and it would be irresponsible of us to set out in public investigatory steps being taken.
“We are actively supporting our students, and will continue to do all we can, including engagement with the statutory authorities, to ensure that all our students feel safe within our college community.”