The Clarkstown School District plans to lock down one of its schools Thursday evening following a bomb scare Wednesday morning, the second such incident in two days.

At about 5:30 a.m. Wednesday, a custodian at Nyack High School found a note on the front door threatening a bomb was inside this school. The school was checked by police and nothing suspicious was found. The high school opened without interruption.

The incident followed a similar threat on Tuesday in which graffiti in a stall in the boys? bathroom at Felix Festa Middle School warned of a bomb that would go off on Friday. The Clarkstown School District alerted parents to the matter through a letter. School officials say the incident is mostly likely a student prank.

However, Felix Festa Middle School officials are not taking any chances. They say after classes on Thursday, the school will be locked down and all after-school and evening activities will be canceled. The parking lots and access roads leading into the school will be blocked off. Then a bomb-sniffing dog will be brought in to search the entire building Thursday evening. The building will be locked until classes resume Friday.

There have been six bomb threats in Rockland since the school year began. No explosive devices were found in any of the schools.