The Hendrick Hudson School District is on high alert today after threats forced the lockdown of schools over the past two days.

Police say emergency procedures were placed into effect after the high school received anonymous threatening phone calls on Tuesday and Wednesday.

School officials tell News 12 someone broke into the high school Monday night, smashing a window and stealing a computer. While police were in the building on Tuesday investigating the break-in, a secretary received a phone call telling her the caller knew of the investigation and then made a threat.

Then, just after 2 p.m. Wednesday, school officials say another threatening call came into the assistant principal's office. The high school and neighboring Frank G. Lindsey Elementary were both placed into lockdown.

Not many details about the call are being released, but school officials say the male caller had gone on an obscene rant and demanded money before hanging up.

A sweep of the schools turned up nothing, but both school and police officials say they're not taking any chances. "When these things happen we deal with them swiftly and we deal with them as though the threat is real," said School District Superintendent Joseph Hochreitter.

According to the school district website, a uniformed officer will be at all the schools both today and Friday. So far everything has been quiet, which is partially because a number of students opted to stay home.