The Essex County Prosecutor’s Office is making sure that county residents know that if they make a threat against a school, even as a joke, they will be prosecuted.

Acting Essex County Prosecutor Robert Laurino held a media event Tuesday to relay the message after several county schools were put on lockdown due to threats being made.

“We want to make it clear to young people who think this is a joke or a prank, that they will be prosecuted for this behavior,’’ Laurino said in a statement.

The spike in threats came in the wake of a deadly school shooting in Florida on Valentine’s Day. Two separate threats at different schools took place in Nutley and a third took place in West Caldwell.

Authorities say that 18-year old Nutley High School student Joseph Rafanello was arrested for allegedly posting a threatening video on Instagram. That post was made before the Florida shooting but authorities say that students in Nutley remembered the post and reported it. Police say that weapons were found at Rafanello’s home.

Also in Nutley, a 13- and 14-year-old were arrested for making a threat toward Abundant Life Academy, a private school. 

The West Caldwell incident happened this past weekend. Police say 18-year-old Michael Schmidt allegedly posted a threat via Snapchat against the high school.

Laurino says that parents need to monitor what their children are doing.

“Parents have to remain vigilant in being involved in the lives of their children, be cognizant of what their children are doing on the internet, in social media and in videogaming.”

All of the teens were charged with causing a false public alarm. The 18-year-olds are in jail and will appear in court later this week.