Classes were canceled Thursday at Mamaroneck High School after custodians discovered three threatening messages on walls.

The school?s principal says custodians found the messages at around 7:30 a.m. Officials aren't elaborating on the location of the messages, but they say the threats were not specific. The school was closed as a precaution.

The cancellation gave students an extended holiday. The school is closed Friday and Monday for Memorial Day.

In March, the school was evacuated four days in a row after bomb threats were found. A 13-year-old boy and two 15-year-olds were charged in that incident.