Darien High School's "Senior Fun Day," originally scheduled for Friday, June 11, was canceled due to a senior prank that "crossed the line," according to Superintendent Donald Fiftal.

"[Last] Wednesday night, we believe about midnight, a number of students, who for some reason were out of their homes late at night, went over to the courtyard at the high school. On the pranking side, they hung some banners up, did toilet paper and, with washable paint, wrote `The Class of 2010 Rules,' and those kind of things on the windows," Fiftal said.

"However, somewhere in the group, someone also -- in one section of the brick wall -- had spray painted something," he said.

The spray-painted message was not washable, but has been removed from the building, Fiftal said.

"At that point, then, the prank becomes unacceptable," he said.

An assistant principal at the high school notified the police of the incident at about 3 p.m. Thursday; the department has since increased its patrol at the high school, according to Sgt. Jeremiah Marron.

"Frequently, there's senior pranking. Sometimes it's a fine line when pranking crosses the line and becomes somewhat damaging or inappropriate," Fiftal said.

In addition to the spray paint, a door at the high school was also damaged.

"There were some cars that may have driven onto the sidewalk area of the courtyard, and I think in maneuvering around, one of those cars hit into a door ... which I think was probably unintentional," he said.

"And because it got to that point, the school was going to have a Senior Fun Day [Friday], maybe like a waterslide in the courtyard -- those kinds of things -- fun things for part of their day. But that privilege was not extended because of what happened," he said. Some of the money that had been set aside for the event will be put toward clean-up and repair costs, according to Fiftal.

The student responsible for the spray-painting incident came forward to the administration on Thursday to claim responsibility, Fiftal said.

"That's where educationally, it becomes a learning experience and it's certainly to his credit to come forward and own up to the wrongdoing," he said. While the administration is not certain how many students were involved in the lat-night incident, Fiftal said he thinks it was between about 20 and 40 students. This year's graduating class is made up of 285 students.

"Overall, this is a really nice senior class. I think sometimes some of the members of the senior class feel bad it happened," the superintendent said.