Investigators say they do not believe the threats made against the Hilton Central School District this week came from anyone locally.

During a news conference on Friday afternoon, the Monroe County Sheriff's Office said investigators believe the emails are coming from overseas and that other districts in the U.S. have received similar threats.

Superintendent Casey Kosiorek said a threat similar to Wednesday's was sent out to local news stations again on Friday. Police say it came from the same IP address as the first threat. According to Kosiorek, Friday's email included a new sentence that claimed Molotov cocktails would be thrown into district offices in addition to explosive devices being planted in schools.

Police and district leaders say they determined Friday's threat was not credible and decided not to evacuate buildings. However, out of an abundance of caution, schools were searched by explosive-detecting K-9 units.

The high school and middle school were placed on lockout while the search took place. Elementary students waited on school buses until the searches were complete. Deputies say no suspicious or hazardous devices were found.

The sheriff's office says all students and staff are safe and according to the district, after-school activities will proceed as scheduled.

District leaders say a public meeting will be held Friday evening at 6 p.m. to address the situation.

According to police and the Hilton CSD, the threatening emails made reference to a book located in a district library.

“The threat that came in was based on the fact that a book titled ‘This Book Is Gay’ is a selection in the Hilton library at the high school,” Kosiorek said. “It is also a selection that is available in other schools across Monroe County and in the Monroe County Library.”

According to Kosiorek, the district has a review process which allows parents to contest any books that are made available to students in its school system.

While the sheriff's office is still investigating the cause of the threat, the superintendent says he is considering this a hate crime.