Last week, Stanford University officials launched an investigation following the discovery of several swastikas and an image of Adolf Hitler on a student’s door.

The incident occurred in one of the university’s residence halls, and the door belonged to a Jewish student leading officials to suspect that the symbols were intended to intimidate the individual. In a letter sent to students on Saturday, the university confirmed that its campus safety department is treating the incident as a hate crime. According to the letter, this is not the first such incident:

“This incident unfortunately is one of several antisemitic incidents that have occurred this academic year and have been posted to the Protected Identity Harm Reporting website. It also involves a particularly brazen threat to an individual student, in what should be the privacy of their campus home, which calls for our unusual condemnation.”

According to the Anti-Defamation League, both Anti-Semitic incidents and beliefs have risen in recent years.

Read the full letter sent to students here.