NEW YORK ( CNN ) -- Three professors and a former professor at Columbia University 's Teachers College received hate mail this week , the New York Police Department said . It 's the campus that was shaken by several bias crimes directed at black and Jewish professors in 2007 . Columbia University 's Teachers College is once again the target of a hate campaign . Three professors received manila envelopes Tuesday with images of swastikas in them . The fourth , a former professor who is an African-American , was sent a manila envelope containing an image of a noose , according to NYPD deputy commissioner Paul Browne . Among those receiving a swastika image was Elizabeth Midlarsky , a Jewish psychologist who has studied psychological principles in the context of the Holocaust , police said . In 2007 , her office door was spray-painted with a swastika . ( A swastika is the right-angles cross symbol used on Nazi Germany flags ) . The NYPD Hate Crimes Unit is leading the investigation into the incident . No arrests have been made . `` The TC community deplores these hateful acts , which violate every Teachers College and societal norm , '' said an e-mail Wednesday to faculty and students from the college 's president , Susan Fuhrman ; and dean , Tom James . No arrests were been made in the 2007 incidents . Police declined to say if they believe there is a connection between those cases and the mailings this week .
Three professors , one former one at Columbia University receive hate mail this week . Jewish psychologist at Teachers College among those receiving swastika . In 2007 , same psychologist 's office door was spray-painted with a swastika . Comment: