My colleague Richard Liebson reports that a 12-year-old South Salem boy’s Internet blog item prompted Valhalla schools to go into “lock out� mode and kicked off a series of security procedures that eventually involved the Mount Pleasant police, the Westchester County District Attorney’s office, Somers state police and the Chicago police department.

“In the end there was no threat, but the school district did exactly what it should have done,’’ Mount Pleasant Police Chief Louis Alagno said of Thursday’s incident.

It began at about 1 p.m., when Valhalla Schools Superintendent Diane Ramos-Kelly received an e-mail from someone quoting from a blog item that Alagno said “could have been perceived as threatening.’’

Ramos-Kelly immediately contacted Mount Pleasant police and ordered a “lock out� at all of the districts school buildings, which kept students and staff members inside and restricted entrance to the schools. She also used the district’s message alert system to advise parents of the situation via telephone.

“Police told us there was no immediate, serious threat, so we didn’t go into a lock down mode, which would have kept everyone in their class rooms,’’ Ramos-Kelly said yesterday. “Nevertheless, we live in a world where you can’t be too careful, so we decided that the lock out procedures were appropriate. When it comes to the safety of our kids, we don’t play around.â€?

Mount Pleasant police sent the e-mail to the District Attorney’s high technology crimes unit, and as a precaution, stationed two youth officers inside the Valhalla Middle/High School and had two uniformed cops patrol the campus.

In the meantime, Alagno said, the DA’s office traced the e-mail to a woman in Chicago. Police in that city were notified. Chicago police interviewed her and determined that there was no threat. The DA’s office was also able to trace the original blog item and discovered that it had been written by a 12-year-old South Salem boy. State police and Mount Pleasant detectives interviewed the boy, but did not arrest him.

“There was no threat, and there was no crime,’’ Alagno said. “State police are talking to the boy’s parents about it.â€?

While the incident “turned out to be a lot about nothing, I have to say that the Valhalla School District handled it very well,’’ Alagno said. “They are one of the most pro-active school districts in the state in terms of security and they proved it in this incident. Everything worked the way it’s supposed to.’’

Reach Richard Liebson at rliebson@lohud.com or 914-694-3534.