School President Jeremy Travis sent a letter recently to students and professors reacting to an Associated Press report on the 19-year-old informant, who says he quit working for the NYPD at the end of the summer after growing uncomfortable with the job.

In the letter, Travis said he was unaware of the spying, and expressed concerns about using informants for surveillance where there is no evidence that anyone committed a crime.

NYPD spokesman Paul Browne wouldn't comment on Travis' concerns. He said the department isn't admitting that the informant actually worked for force.

(Copyright 2012 The Associated Press. All rights reserved.)