A new rash of anti-semitic graffiti broke out this week at Boston University in Warren Towers, the university's major dormitory. Wesley J. Christenson, director of Boston University's public relations, said yesterday.

Christenson credited the most recent outbreak of a problem which has plagued B.U. for several years now to the actions of a single person. "It's probably just some deranged lunatic on the loose with a can of paint and a crayon," Christenson said.

Nevertheless, school officials expressed concern over the more intense anti-semitic feeling reflected in several acts around campus this past year.

In one such incident last October, a student defaced the walls of the Hillel House--a campus center for Jewish students--with swastikas and anti-semitic slogans, Christenson said.

Tensions increased on January 29 when an artificial bomb, fashioned out of a coffee can and an aerosol deodorant can, appeared in the elevator of Warren Towers. A note attached read in part, "Others had tried to kill the Jews but failed."